Just my personal opinion following, ok?
Keep 3700X or wait a bit for new gen. CPU? Yes, next gen CPU's will be better. How much better? Nobody knows. But one is for sure: they will be quite more expensive. For example, 3700XT (released few months ago) is ~50€ more expensive than 3700X, but performance difference isn't really that big. In short, I expect newer 8C/16T AMD CPU will bi quite better than 3700X but also quite more expensive -not only 50€ difference!
I think, new 8C/16T CPU price will be closer to current price of 3800XT. Why's that? Because electronics supply is kinda poor lately (covid issue, etc) and Intel competition is quite weak.
In short: I would keep 3700X (is CPU I have actually) simply because right now, it has excellent price performance ratio. However, if your budget isn't that tight and you're not in hurry, then you better wait a month or two. Decissions, decissions..