If you're struggling to find a 6800 XT, the RX 6800 is a viable alternative that's usually on sale for less than $550 with slightly lower performance. When it's in stock, it's possible to find them for less than $600 (at the time of writing there are some models for $550), but the supply situation is pretty volatile, and individual models go up and down in price fairly regularly. The 6800 XT really only has one problem: supply. We'd recommend against the 7900 XT since it's only about 25% faster according to most reviews, and enlarging the budget to over $2,000 just for that isn't worth it.

But perhaps you might consider the RX 7900 XT, which is about $250 to $350 more expensive. It's also quite competitive against the RTX 3080 and even the RTX 3090, especially at lower resolutions, though obviously, you're not considering those cards for an all AMD build. In actual gaming benchmarks, we see that the 6800 XT barely lags behind the 6900 XT, as expected. However, it has 128MB of Infinity Cache and 16GB of GDDR6 just like the 6900 XT, which means the 6800 XT will theoretically have at least 90% of the performance of the 6900 XT whether it's games or professional applications. The 6800 XT was AMD's number 2 GPU from 2020, with 72 Compute Units (or CUs) out of the maximum 80 that you'd see on the RX 6900 XT.

Amd ryzen graphics control panel