Just to give you a brief guide in projectors.
Projectors
JVC - best contrasts, best blacks, most expensive bulbs, least forgiving throw distance, very dim on 'low lamp mode' but comparable brightness on high lamp mode BUT they're noisy at this stage (lets say 3.5/5 noisiness), expensive bulbs £399
Models: X5900, X7900
Sony - second in class contrast and blacks but best motion and picture processing (IMO they're really good at this). They normally lack the lumens unless you're going for their lasers which are around £8,000
Models: VW550ES+
Epson - very quiet in medium or eco mode, as bright as the JVC in high lamp mode (well near enough) without being as loud, contrast and black floor are worse than the two above, very flexible in terms of placement, very very bright in dynamic and high lamp modes which is great for white walls, cheap bulbs £99
Models: 9300, 9400
Room treatments
Getting the best from your projector IMO has two easy paths:
1. Paint the room black and black velvet
2. an ALR screen
Painting and treating the room is the best and allows you to get the most from your projector.
ALR screen's combat ambient light by rejecting light from the sides. they're good if you want to watch a PJ with the lights on. However, if the throw distance is short, you can have some hotspotting (centre of image brighter than the peripheries) and poor viewing angles (not an issue for one person IMO).
If you cannot paint or treat your room, you leave a LOT of performance on the table re: contrast and blacks - in which case a JVC or Sony might be money down the drain where you'd be better off treating your room or getting an ALR/grey screen.
HDR
HDR on projection is a minefield. Basically dynamic tone mapping is needed on projection to make the bright images look good without blown out highlights and the dark scenes look good whilst maintaining shadow detail.
There are 4 common solutions to this:
1. a JVC N series projector or above £5000+
2. MADVR HTPC £1000+ (also doubles as a PC and a gaming computer and a media server and media player but will not apply HDR to any non-local source; has to be played via the MADVR player)
3. Lumagen £5500+
4. MADVR Envy £7500+
UST vs Long throw
Generally UST are for very very casual people. They aren't very smart solutions for an audiophile such as yourself as the centre channel position is going to be horrible and will impact performance, no matter what someone tries to convince themselves. They also offer inferior contrast and PQ compared to the longer throw more cinematic projectors.
Pair the right projector with the right room and treatments. As your setup changes, you can always trade up gear.