Recent examples? For 3rd party I honestly don't know, but then again I haven't actually gone around looking for examples. If I had the time, chances are I could find a few. For 1st party I think it's generally a given; look at the results of games like Days Gone, GOW4, or the upcoming TLOU2. It's probably safe to say they all utilize some GPGPU capabilities of the PS4 hardware since they're 1st party and have the privilege of doing so.
I think we should probably hold off a bit before even claiming MS is going gung-ho on cross-gen support. Plans might've changed on that note. And IIRC Booty's comment was at E3 2019, so I'm guessing it was applicable to games coming that summer through to summer of 2021.
I doubt most 3rd parties will leverage the very specific strengths of either system tbh, just as you, but I've been talking about this stuff in terms of what the 1st party teams can potentially do, because they'll have the leeway and support to do so. Most of the time, there'll be feature parity and maybe some resolution differences, again as you've said.
Theoretically yes, dropping resolution on a 36 CU GPU should allow for a push of 1st party games at parity to a 52 CU including in terms of compute, since the two systems are essentially using the exact same architectures. But I figure it would depend on how the game is using the GPU and for what resolution methods. For example if the game's tying resolution range to be inter-dependent on model polygonal complexity and distance from the player, dropping resolution might also drop the complexity of the character model, which could be very noticeable the closer they are to the player's character.
A quick example of the possibilities, anyway.