Not 100% sure about the chassis and compatibility with the rest of your rig so hopefully someone follows up on me, but in general I would try getting the AMD 9070 XT if you can find it near its real price ($600). That might be a bit difficult since it just released, so I would wait until it starts being more available if you can.
If not that, I'd recommend the 4060 Ti (16GB). Note that there's an 8GB version too, do NOT buy that one. Nvidia is generally better when it comes to running AI, but the new AMD gpus are pretty good too.