There is NOTHING you can do to make projectors look better when reproducing HDR. They do not get bright enough to provide all the benefits of HDR. And because they don't get bright enough, the color gamut is not expanded very much unless you have a very bright, very expensive projector. That said, the newer projector should look better than the older projector. Have you confirmed that the lamp that is installed is fully and properly seated within its assembly AND that the assembly is fully inserted or latched into place? The other thing you have working against you is that honkin' huge screen size. The Benq projectors aren't that bright to begin with (no inexpensive projectors that you would want to watch movies on are very bright). Last Benq projector I used, probably 4 years ago, was one of their circa $2000 models and I would not produce more than 29 fL on an 82-inch wide screen. On a 120-inch wide screen, you are likely not getting more than 18 or 19 fL in Normal lamp mode and it would be less than that with the projector in the most accurate picture mode. SMPTE calls for 12 to 20 fL for 100% white(for projected images) in standard dynamic range. HDR specs go even beyond 1000 fL. So for HDR content, the limit for 100% white isn't probably going to be brighter than. Using Eco mode drops 100% white in the 10%-20% range... I forget where Benq fell on that range.
Essentially, when you have a projector/screen combination that can't produce more than 100 fL for 100% white in HDR mode, the projector is not going to produce very impressive HDR images. I would turn off any picture controls with "Auto" or "Automatic" in the name. The exception being auto-iris if the projector has that. Also check for manual iris or settings menu iris controls and make sure the iris is set to fully open all the time. With a screen that large, you never want an iris to further reduce your available light. This issue with projected images and the brightness capability of the projector and screen combination are the reasons that projected video is going to disappear in favor of large format LED screens. This will happen even in movie theaters. When projected images get bright enough to start looking good, you run into problems with having so much light reflecting back at the screen, even in dark rooms, that the reflected light washes out the projected images causing loss of shadow darkness.
Manufacturers who claim projectors specifically for movies are bright enough to use with a 150-inch or even 300-inch projection screens do no favors to any customer by suggesting for even a moment that they would have a great viewing experience with a screen that large and a projected image that dim. Yet every set of specs for even inexpensive projectors claim 300-inch wide screens are useful with that specific projector (well almost all of them, occasionally you might see one that's OK up to maybe 75-inches wide, and they say "up to 150 inches" which will produce exceptionally dim images from even some **** expensive projectors. When I was calibrating systems, people were freaked-out that their setup could produce no more than 8 fL for 100% white in standard dynamic range. There's no magic bullet to make an image brighter if the iris is wide open (if there is an iris) except making the image smaller or make the screen have more gain... but it's hard to find a screen with 1.4 gain or more than doesn't produce a ball of mosquitos right in the center of your field of view, called a hot spot (it's not a bright spot, it a spot where you see this grainy ball overlaying the part of the image you are looking directly at. It's an artifact of the screen surfaces/coatings that produce gain.
Oh, back on the topic of why the projector may seem dim... the hour meter on projectors is easy to reset... sure it SAYS circa 1000 hours, but how do you know the hour meter wasn't reset to zero when the lamp had 2000 hours on it and now that the hour meter says 1000 hours, the lamp COULD have 3000 hours on it, not 1000 (edited 2-24-21) hours. The seller may not even know that. So your lamp might only be outputting 50% of the light you get with a fresh lamp. Another issue is companies that sell replacement lamps for $40 when the manufacturer wants $180 or even $300 for a replacement lamp. Sometimes the replacement lamps LOOK identical in every way, but there's nothing guaranteeing that they are as bright as the "real" lamps the manufacturer uses and sells--the inexpensive replacements CAN be just as bright as the original factory lamps. There's just no way to tell unless someone has measured their projector with a new lamp and has used several inexpensive replacements and also measured those when new and they were close to the original lamp in brightness. If your projector has a zoom lens, you can lose as much as half the light on the screen by choosing the wrong amount of zoom. The problem is that you can't find the the brightest setting for a zoom lens by eye, you really need a light meter... it is POSSIBLE (not that I've tried) a phone app that uses the camera as a light meter (if there is such an app) MIGHT be useful for this if you can setup the phone so it always "sees" the same part of the projection screen (not hand-held and not moved as you try different amounts of zoom. You will have to move the projector closer/farther to keep the image filling the screen and not getting too small, and not overflowing the edges of the screen more than a few pixels. If you don't move the projector, any measurements you make won't be useful for finding the brightest zoom setting.
Essentially, when you have a projector/screen combination that can't produce more than 100 fL for 100% white in HDR mode, the projector is not going to produce very impressive HDR images. I would turn off any picture controls with "Auto" or "Automatic" in the name. The exception being auto-iris if the projector has that. Also check for manual iris or settings menu iris controls and make sure the iris is set to fully open all the time. With a screen that large, you never want an iris to further reduce your available light. This issue with projected images and the brightness capability of the projector and screen combination are the reasons that projected video is going to disappear in favor of large format LED screens. This will happen even in movie theaters. When projected images get bright enough to start looking good, you run into problems with having so much light reflecting back at the screen, even in dark rooms, that the reflected light washes out the projected images causing loss of shadow darkness.
Manufacturers who claim projectors specifically for movies are bright enough to use with a 150-inch or even 300-inch projection screens do no favors to any customer by suggesting for even a moment that they would have a great viewing experience with a screen that large and a projected image that dim. Yet every set of specs for even inexpensive projectors claim 300-inch wide screens are useful with that specific projector (well almost all of them, occasionally you might see one that's OK up to maybe 75-inches wide, and they say "up to 150 inches" which will produce exceptionally dim images from even some **** expensive projectors. When I was calibrating systems, people were freaked-out that their setup could produce no more than 8 fL for 100% white in standard dynamic range. There's no magic bullet to make an image brighter if the iris is wide open (if there is an iris) except making the image smaller or make the screen have more gain... but it's hard to find a screen with 1.4 gain or more than doesn't produce a ball of mosquitos right in the center of your field of view, called a hot spot (it's not a bright spot, it a spot where you see this grainy ball overlaying the part of the image you are looking directly at. It's an artifact of the screen surfaces/coatings that produce gain.
Oh, back on the topic of why the projector may seem dim... the hour meter on projectors is easy to reset... sure it SAYS circa 1000 hours, but how do you know the hour meter wasn't reset to zero when the lamp had 2000 hours on it and now that the hour meter says 1000 hours, the lamp COULD have 3000 hours on it, not 1000 (edited 2-24-21) hours. The seller may not even know that. So your lamp might only be outputting 50% of the light you get with a fresh lamp. Another issue is companies that sell replacement lamps for $40 when the manufacturer wants $180 or even $300 for a replacement lamp. Sometimes the replacement lamps LOOK identical in every way, but there's nothing guaranteeing that they are as bright as the "real" lamps the manufacturer uses and sells--the inexpensive replacements CAN be just as bright as the original factory lamps. There's just no way to tell unless someone has measured their projector with a new lamp and has used several inexpensive replacements and also measured those when new and they were close to the original lamp in brightness. If your projector has a zoom lens, you can lose as much as half the light on the screen by choosing the wrong amount of zoom. The problem is that you can't find the the brightest setting for a zoom lens by eye, you really need a light meter... it is POSSIBLE (not that I've tried) a phone app that uses the camera as a light meter (if there is such an app) MIGHT be useful for this if you can setup the phone so it always "sees" the same part of the projection screen (not hand-held and not moved as you try different amounts of zoom. You will have to move the projector closer/farther to keep the image filling the screen and not getting too small, and not overflowing the edges of the screen more than a few pixels. If you don't move the projector, any measurements you make won't be useful for finding the brightest zoom setting.
