If you are playing at 1080p, then you’re gonna need at least an RTX 2060 to play Quake 2 RTX with decent frame rates, that too after reducing lighting quality by a notch.
Source: N4G PC Quake 2 RTX Performance Review: 30 FPS w/ GeForce RTX 2080 Ti @ 4K, 45 FPS with 2080 @ QHD