GPU: AMD RX 6900 XT
CPU: AMD Ryzen 9 5900x
Headset: Reverb G2
Windows 10 21H1
There are quite many people observing better performance (for months or even years) when the game is out-of-focus. However, this seems to be not limited to MSFS only; I do experience the same with DCS for example.
My GPU is AMD, yours is nvidia. So I guess it’s not related to the GPU manufacturer.
Maybe it’s a Reverb G2, OpenXR or Windows Scheduler issue.
Some people have reported that enabling optimiziation for Background Services helps, others reported that giving the game only a few CPU cores and/or making the game process Low Priority helps. But not for me.