ok, so here is the procees i followed to set the voltage, no need to do all benchmarks, once MSIAfterburner is running you can see the curve voltage/mhz, i just took a point where the curve start going flat.
https://forums.serverbuilds.net/t/guide-overclocking-the-right-way-on-nvidia-gtx-and-rtx-series-cards/4408/4
and for all parameters MSFS, NVIDIA, Quest 2, ODT i follow this post
https://forums.flightsimulator.com/t/quest-2-2080ti-link-fs2020-set-in-ultra-best-performance-simple-setup-guide/346291
tell me if u achieve better results too 
nota : the 1st post doesn’t list the RTX 3xxx but it works the same way apparently, the goal is not to overclock, but to set up and fix the levels of voltage/Mhz