I'm sorry you are having problems. After a week with mine, I have no issues and love it. I took the face padding off and can put on the cosmos with my glasses no problem. With 1 PD everything is clear and I can read all the gauges except some of the super small ones. I have no mouse or menu issues, so unfortunately I don't have a solution for that.
The sound is good, not sure what you mean by the headphone mounting brackets flipping up, haven't experienced that.
I did have to turn things down slightly, but I can get 45fps on the ground and it just goes up from there. I'll try it online this weekend and see how that goes.
As for other games not working, well you have dcs what else do you need?
if only starcitizen used Vr like they said it would.
Overall, no complaints except the price.
9900k @4.8, 2080ti and running dcs on a wd black m2