Yes it does vary by game.I'm not sure what you've been looking at. It's a complete 50/50 depending on game though. The 5700xt averages about 15% slower than the 3060ti.
And the suggestion is the 6700xt is 10% faster than the 5700xt so it's price/performance is right there with the 3060ti from that then.
There are plenty of games where the 5700XT is slower than a 2070S. Plenty.
And apparently the 6700XT is only 10% faster (then the 5700XT).
Gen-on-gen that's really poor. Isn't RDNA2 supposed to be loads more efficient? And yet (allegedly) they've only been able to make a card that's 10% better for £400.