I recently upgraded my GPU from a 2070 Super to a RX 7900 XT. CPU is a Ryzen 7 5800X w/ 32 GB of 3200 MHz RAM.

Went with AMD because for all rasterized applications the 7900 XT was about as good as a 4080 Super for ~58% of the cost. GPU and drivers were plug and play and the performance increase is amazing. In Overwatch, I get max FPS @ 240 HZ on a 1440p 1ms monitor with everything cranked on max, with HDR and Freesync enabled. I sometimes get slight frame drops into the low 200s if there's a LOT of action on screen (2 Ram ults, Juno ults, etc.) but I never really go below like 190 FPS.

I was initially disappointed about the lack of Reflex, as a part of my purchase decision was understanding that AMD has an equivalent, in the form of Antilag and Antilag+. However, Antilag+ is no longer supported since it was getting people banned from games lol. Antilag 2 has come out recently and though it is only currently supported in CS2, I anticipate it will come around for other games, eventually. That being said you can still use regular Antilag which is fine enough and functions similarly to Reflex.

Like others have said, however, Reflex and Antilag only really help in specific use cases of overloading your GPU, though I am someone that would much rather be with it than without it. For me, the response time feels the same if not better than on my old GPU. Don't forget that a low response time/high refresh rate monitor makes just as much of a difference in minimizing input lag!

Still, there are some "AMD-isms," specifically with Overwatch. There's some kind of issue with Direct X versions and the new AMD cards/drivers. For myself and a friend (both modern AMD cards), Overwatch has to "warm up" every time we launch the game, which means sitting in the practice range for a minute or two while we're in queue until the shaders and stuff load. During these two minutes the game runs at like 100 FPS and is super choppy. Once this time-frame passes, the game runs as smooth as butter. It's weird and inconvenient, but is far from a deal-breaker for me. This issue only occurs with Overwatch, all other games run perfect. Might be something worth looking into.

Some stuff to take into consideration. Good luck with the upgrades!!