Suggestions/recs for upgrading a GPU and RAM

PC: DELL Precision Tower 5810 (I'm assuming this should give correct info on the motherboard)

I'd like to know what GPUs I should look to save for to upgrade my Windows 10 PC's current GPU, which is a Quadro M4000, within ~ 6 months or so. Goal is to be able to play recent/soon-releasing games (specifically, Ace Combat 8) that're graphically intensive at ultra quality, 1080 and still get solid, steady performance (60 fps or so? idk) without having to overhaul the CPU and motherboard too (so at minimal cost for maximum impact, in a sense).

Ideally, no RGB (opaque case anyway). Budget < 1k CAD, location is QC, CA.

(Will respond to (reasonable) requests for additional info in comments and edit them into this post as well)