The relative performance table below the specs can help you. The cheapest you can get right now is a rx 6600 dipping below 200 $/€, but the 6600xt 6650 6700 6700xt are also viable. The 66xx range is enough for 1080p, 1440p begins with the 6700 becausa it has a 10gb vram buffer and wider pci bus.