That's strange. On my Quest 2 in HereSphere, I get over 100Mbps download, and over 250Mbps upload with speedtest by Ookla. Is your xbvr server wired to your router, or is it also using wifi? I'm able to play 100Mbps videos over XBVR without any issues. If you exceed 200Mbps bitrate, then the Quest 2 might just not be able to decode the video fast enough (rather than it being a wifi issue).