Donux I've done precisely this - I was forced into it and I can confirm that the 15" 2015 that I have at least does not have PWM, and uses an 8-bit display without dithering. I can also confirm that it is visually identical (to my eyes) to the display on the 13" version. It is the newest and most powerful Apple laptop I can use. Though I'd say that in my case, even the PWM-free MacBook Airs (M2 onwards) cause me issues that I can't explain, but that could indeed be temporal dithering, which I didn't know about that when I last tried one.
Depending on your workflow, it can be manageable (make sure you get the very best config, 2.8 Ghz and 16GB of RAM), but OS support is a problem, even with OCLP. Sequoia + have major issues particularly with Xcode and metal frameworks, leading to crashes within the graphics stack when debugging with Xcode (note that the applications themselves run mostly fine when not bridged to Xcode).
Compared to the 13", it is much more powerful - I switched from the maxed out config of the 13", with the dual core 2.8Ghz i7. The extra two cores, and increased thermal headroom of the 15" makes more than a 2x difference in many situations, and the GPU is also useful in some scenarios as well. The 13" is really unusable at this point IMO, whereas the 15" can still just about manage. Be prepared for a fair amount of fan noise though, and because the heat sink and interface are so tiny, it's really not something that magic thermal paste or pads are going to fix (I've tried everything…).