"The RTX 5090 is anticipated to deliver 50-70% performance improvements across the board compared to the RTX 4090 – particularly excelling in 4K resolution. And with 4K 240FPS gaming on the horizon, the RTX 5090 will be perfectly positioned to tackle the most demanding gaming scenarios." ... but will cost a tall stack . 4090 still costs a pretty tall stack .
IMHO; If you're rich, get 'em both . If not, throw something from the closet in it, and wait :)
P.S. What happened to your other post ?
Too The Moon !