I have the 12 speed slx cassette and shifter, XT derailleur. I’ll see how the NX is, can’t pass judgement yet as never used it, if I cant tell the difference I’ll leave it as is.
Probably a little slicker and smoother than NX Eagle – Sram stuff is a little clicker I’d say (which I prefer but many don’t). Sram NX cassette will be on a normal Shimano style freehub – to get SLX or XT 12 speed cassettes on there you’d need a microspline freehub body for the hub. I’d imagine you could get that for a DT Swiss wheel but not sure of the cost.