What HMD? For a rift something around the power level of a 1080gtx is pretty ideal. Overkill really, but it'll let you turn on supersampling on a lot of titles. 2070 should work. The 1080ti would be better at the same price of course, assuming you don't care about the RTX feature set.
For 1440p pancake gaming do you care about high refresh? Do you have an adaptive sync monitor?