I don’t know how much impact VR has on a system. Reading through the topics here there seem to be some “startup” problems with VR, but I’m sure they will be solved in the near future.
As you’re planning to use VR I’d consider a future-proof GPU like you already said. But keep in mind FS is a complex program and can’t be compared with other Games. I’m mentioning this because you may get ‘wrong results’ when you watch the 3080 perform on YT game video’s or benchmarks.
I think you’ll have to recon with the limitation of your CPU when you buy a 3080. Meaning, you’ll have to hold back your GPU because it wants to go at light speed. And that’s where disciplined tweaking will be needed.
I"m not sure what the result will be when you “just” limit FS to the max of your current CPU (I7-7700). You can try to find YT video’s of simmers who run there FS on unbalanced hardware (I7-7700k and a 3090) for example. I’ll keep an eye on this post, and if you have any questions I’ll be happy to advice you if I can. At the end I’m also aiming for the best upgrade for my FS goals.