I remember seeing RDR 2 GPU-scaling/CPU-scaling videos on YT, and a GTX 1660 maxed out with around a Skylake i5-6500 quad-core. So that would basically be a ceiling for you.
Some under $200 GPU choices.
Yeah, yeah, I know. 🙁God that's a depressing video. GTX 960 for $200 felt like a joke in 2015 and now it really feels perverse only a couple of months out from 2022.