I'm running all ultra on 4 years old hardware with a 1080TI (3 years).
Getting a steady 60+ FPS except in some very specific areas where it'll fall into the mid 40s for a second or two. It's noticeable but nothing worth throwing a tantrum over.
If you asked for proof, nah, I wouldn't provide any. Not because I'm lying but because I don't really give a damn and I've got nothing to prove. Not to mention it would serve absolutely no purpose. Everyone's experience can be vastly different.
I run it at a Xiaomi 9T on 4K 60fps Stadia ftw