I remember that about 15 years ago, there was another cloud service that allowed you access to a virtual machine for something like 15 minutes that you could reserve to test a given library.  I can't remember the name of the service and the likelihood that it's survived is tremendously unlikely, as such services can be absolutely fraught when it comes to ToS concerns.

You could also try local sound studios or even a nearby University, both for recommendations or even being able to freely or affordably try things out.

I know that most of the composers I know who want a woodier sound "render" out to an acoustic that's close-miked with a midi like a QRS or Disklavier system.

It's been a long time since I seriously shopped for a PTQ alternative, but I remember that Imperfect Samples had more "woody" vst options than most providers (but that's probably a decade-old opinion).

If I were in the market for more Piano VSTs, I'd probably either go for VSL's Fazioli (please PTQ...please add a Fazioli!) or just save up to get a rebuilt golden era grand and add QRS to it--but I so don't have anywhere to go with an acoustic of any real size in my studio.  Once you get to the point that a "good" controller/keyboard is $3-6K USD plus another $500-1K USD for a good library set, you may as well consider an acoustic for $6-10K USD, as those price points start being more about business investment and future value.  Spitfire also has decent pianos from what I've heard, but my experience outside of the PTQ market is too minimal to provide top-quality advice.

Vienna Symphonic Library has demos sometimes once or twice a year (often with a new piano release, which seems imminent), and they're known for good playable pianos and a sub-par resonator, so it makes a nice pair with Pianoteq's phenomenal resonator. Olivier has a few demonstrations of how those sound in combination, but you could also try for yourself during the next VSL demo period. They also have a 14-day return policy if you don't want to wait, and you can resell your license down the road.

Another very playable piano is the Modern D, it's a new (not fully broken-in) Steinway, but its playability is the best I've seen in a sample library and it sounds very good. There is no demo available with the Modern D, though, and I don't believe you can resell the license.

Native Instruments Noire is probably the warmest/woodiest piano I have. The standard library isn't as playable as the aforementioned libraries (staccatos aren't quite right), but it has good dynamic range and it's still one of my favorite timbres. The felted library is quite nice (it comes with both). You can get it "used" and likely resell it for a similar price if you don't like it.

Am I right in thinking basically none of them have demos? You just have to buy based on audio tracks?

If you had to buy one, which would it be? I just want something to make deep chords sound a but fuller and woody