On my gaming/simming machine my downlink maxes out at 400 Mbps, with MSFS downloads varying wildly, anywhere from 100 to 350 Mbps.
I’m in Portland, Oregon on Comcast cable, which apparently has a pretty good connection to Microsoft’s servers – the fact that people elsewhere having speed problems have reported significantly better speeds when on a VPN makes me real suspicious that network issues are behind the poor speeds some people see – this is something probably Microsoft runs, like an Azure content caching service.