I don't think you understand how the Switch Pro would be able to accomplish 4K resolution. This isn't a "pure" 4K like the PS5 or Series X does. It would use DLSS, which is essentially a high-tech upres solution, and would only effect the Switch in docked mode. It would take the current Switch games in 1080p, and display it in up to 4K through DLSS.
In handheld, it will still only be up to 720p, so it won't be much more capable than the current Switch and Switch Lite. This is why I don't think there will be any games that will be compatible only with the Switch Pro.
Interesting, I didn't realize that 4K would only apply to the docked mode. Yeah, that is pretty exciting. Hopefully the rumors are true.