A lot depends on the headset and the ecosystem you’re using. Lets take the Reverb G2 as an example.
Connectivity is via Display port, USB 3, and also a separate power brick. It uses the Windows Mixed Reality eco system, but also works with Steam VR but theres a number of different apps you would need to download to get it all up and running.
Currently, there seems to be a problem with that headset using some of the new big NAVI gpus and also some compatibility issues with X570 chipset motherboards which mean some people are having to buy a separate powered USB expansion card to drive the headset.
Once connected, the headset is fairly simple to setup, there’s a nice little wizard to walk you through etc.
Now on to the big one, will it affect FPS. the short answer is yes, your driving (in the case of the G2) 2 X 2160 X 2160 screens but there are ways to tweak performance within steam VR and Windows Mixed Reality so you don’t have to have a 3080 to use it. The longer answer though really depends on the Sim or Game and how well they have managed to optimize for VR. For MSFS we dont know yet how impacting it will be, all we know is what the rumours suggest which is its “awsome” .
Bottom line is if you havnt used VR before definatley take your time to research the various headsets and ecosystems they are connected to and get the best headset for you, every single one has their own pitfalls and downsides so you have to figure out what your willing to sacrifice to gain in other areas. my personal decision on the G2 was based on the fact that i primarily use Sims (racing and flight) so some of the dowsides of controller tracking for this headset shouldnt be a problem and the clarity and resolution far outweigh the slightly narrower than some FOV, I’m also happy to spend a bit of time getting it working properly, so thats where my money went.
You may decide that your willing to sacrifice some clarity and resolution for a simpler setup or better controller tracking so as with all these things it becomes a your mileage may vary type thing.