Projector comparisons

@esthlos13 Projector People is an online retailer of projectors and accessories. You can find them by using a search engine.

In my experience JVC's projectors provide superior image quality, and I've also heard good things about Sony in previous years. So my recommendation for brands is aligned with auxinput. JVC's projectors also have auto-calibration software although it can be fairly confusing and tricky to use at least on the older models.

I also recommend getting an HDR 4K (probably with shifted faux-4K, considering your target parameters) projector with that supports 18Gbps HDMI connections. Some faux-4K projectors only support 14Gbps HDMI connections (e.g. some Epson) which is going to create problems for you. In addition to the increased pixel detail, HDR provides more realistic colors. You won't get the same maximum brightness from a projector that you can from a regular TV, so the brightness part of the HDR will be less of a benefit. Some people prefer to convert 4K HDR sources to 4K SDR because of that.

Video projection is like a whole other system. Light control, being able to darken the room, and the screen, are almost equally important. The most important factor in video is contrast. Most people with plasma are used to watching with a lot of room light. But there's a reason every movie theater is dark. And red. With a big screen the light off the screen itself reflects back onto the screen washing out the picture. Even the background color affects your perception of screen colors. There's a reason my room is painted a fairly dark neutral gray. And the screen is a Grayhawk, same brightness and color but much less washout. https://systems.audiogon.com/systems/8367 Also the wire you use matters just as much as with speaker cables. The difference with a really good video cable is like going from 1080i to 4k.  

There's really no point in buying used. You will figure out after some years the bulb thing. Just buy new. By which I mean new new, not last years model new. And don't waste money. There's a ton of people throwing $5k to $50k and more, and you have to strain and get technical to see any difference from the $2500 model. There's more difference by far to be had from the cable, screen and room that anything you can get for any amount of money if those aren't all optimized.

That's why I say projector people. They know projection. 

You married well. 

I have 65" Sony (Android TV).  Black levels and contrast are exceptional.  I know that Sony makes 85" TVs (less than $4k).  20 years ago I had Samsung DLP.  Color wheel made noises and bulb was expensive to replace.  AFAIK all movie theaters use DLP but it is 3 digital mirror systems (no color wheel).  Technology likely improved, but i wouldn't like moving elements in my TV/projector.

thanks for the feedback.  The reason I'm thinking used is that practically speaking I'll only be able to use it so much, and I tend to consider "cost per use" when purchasing anything (or at least most things), thus something like a high end watch, when value over time, actually works out well in this approach.   I'm okay with not having the latest and greatest (though I do prefer) and though I love my Panasonic VT60, I'm sure even a several year old projector will be a completely different experience based on size of picture alone, and I can deal with some minor imperfections.  I notice the higher end Sony's have, according to the reviews, much better lenses and auto features, but don't know enough about this space to be able to adequately balance out those features vs. HDR/HLG, etc.  My room shape may change at some point as well, so a projector that affords setup flexibility is important. I'm also looking for HDBaseT compatibility as the run from equipment rack to proposed projecter site is tricky and will involve a long run of cable. My marantz AV8802A does not support that, but I believe there are devices that can be inserted at both ends.  There's a lot to consider! however I'm not on any fixed timeline so will continue the research.