>>418803751
If you're just looking for free stuff to make sure it's not an issue with your setup, you could try The Lab or the VR mod for Half-Life 2.
The original Assetto Corsa runs better in VR than most other sims I've tried (iRacing, RF2, ACC). Dirt Rally 2 also works pretty well too if you're fine with running rally.
Not sure you really have any options other than VTOL VR for flight stuff, and that's probably simplified more than you'd like.
Only option besides getting a better card for DCS is turning settings way down. MSFS has even worse VR performance from what I've heard, so I doubt it'd be any better.