Currently I'm finding prices for a whole PC upgrade to a 2080ti and i9-9900k with 32gb of Ram a bit too high right now. Most setups are over $2600.. As much as I would like to upgrade for the bit of performance boost, I don't believe the 2080ti was a big improvement from 1080ti to justify. I will patiently wait til Nvidia reveals the next gen graphics cards. Of course I can't speak for others because this would be a great upgrade.
Have you tried Motion Reprojection? Where the headset only runs at 45fps but imitates a second image to give the illusion of 90fps? That's what I use for heavy dense cities.