My wife has been gaming on a fourth-gen i5 + RX 570 for a few months, and it was mostly fine until Halo Infinite— with that title it was pretty clear that she was CPU bound, with the system chugging on open areas, mob AI, particles, etc.

We upgraded her to a second hand B450 mobo + Ryzen 2400 and that's been fine. Still running on low settings due to the limited GPU, but everything is at least playable. And this motherboard has FW updates that support 5xxx series Ryzens, so there's upgrade headroom there now as well.