I wouldn't upgrade from 1080Ti to 2080Ti, the boost in performance isn't that big. 3080 would be another thing, then again a 4070 would give the same performance with much less power usage.
A friend just upgraded from 1080 to RX 6750 XT, about 30% better in the Passmark benchmark and other overall ratings. But when comparing texture rendering the new card was twice as fast. So although the actual speed isn't that much faster the new card is much steadier in environments where there's lots of textures. He's using a WQHD/144Hz monitor and based on his first comments despite the frame rate being the same with both cards the new one was more fluent.
For your budget the RTX 4070 might be the best bang for the buck option, they seem to sell for 549 at Amazon and BestBuy.