For a nice little 5man, a nvidia 1060 6gb vram or better is good enough, for 4 slaves on settings 1 and the main on settings 5+. On 1080p. Fps set to 60 front and 30 back in isboxer.

Any newer modern gpu with similar or better specs would work fine.

Ideal gpu atm, personal preference, is the Radeon RX 5700 XT, performance to price, for a 5man.

Do NOT buy this version though.
https://youtu.be/OJU8jKIYtS4