My case is a "Rugged Hybrid Protective Case" available from several sellers on Amazon.
It has hand grips and a built in screen protector. It was sorta difficult to get on but it feels great. This seller includes grips for the nubs, which also feel good despite not being lined up properly.
I have mostly been playing Quake, so I'm mainly using the sticks and shoulder buttons, and there no problems there. When I need to hit the d pad to change weapons quickly I sometimes get interference and it switches to the wrong weapon. I just need to get used to it, I think. The other buttons that are recessed in the case also require a bit more precision to hit, but for Quake I only go to the menu or put the Switch to sleep, and neither of those happen in the middle of action, so I mention it to make it obvious that there is a difference vs. no case.
Again, i don't use the touchscreen much with Quake, but the screen protector doesn't seem to interfere. I felt comfortable getting a case with a built in screen protector because I have one for my phone and have no problems with it.
Overall I like it, but as I said, it does slightly interfere with buttons and d pad. Even with that, I would but it again.