I've had good luck at budgeting $500 (probably needs to be $600 or $750 nowadays) for a GPU which is usually 1 or 2 steps below the top-of-the-line ATI or NVidia. That GPU can last me 5-6 years as both a gaming or video encoding GPU.
I'm about to upgrade my computer, so I've been specifying my own personal system. I haven't updated my spreadsheet since May, but this is what I was going to get for my GPU:
https://www.newegg.com/msi-geforce-rtx-3060-rtx-3060-ventus-2x-12g-oc/p/N82E16814137632?Description=rtx%20graphics%20card&cm_re=rtx_graphics%20card-_-14-137-632-_-Product&quicklink=true
So that GPU is actually significantly cheaper than my original statement. Part of the reason I went more budget on the GPU this time was because I was splurging on the CPU and RAM, I was getting an I9-14900F for the GPU and getting 32GB of 4800 high speed ram, as those both ate into the budget. I can always upgrade the GPU later and this GTX seemed like an awesome bang-for-the-buck back in May.
Honestly, it should be more than enough for the 4k video processing I do. Anything else is just gravy for the video games.
I'll probably go through the spreadsheet again in January (or next May) and update the hardware to see what I can get for under $1500.