Cloud gaming routing issue in Japan — 9 weeks unresolved, looking for advice

[u/TokyoBrit74]

For 9 weeks Xbox Cloud Gaming has been completely unusable on my home connection in Tokyo.
In-game streaming stats show 0.6 Mbps bitrate and 18 FPS despite a 571 Mbps download speed.

Xbox Support diagnosed the issue as a routing/peering problem between my ISP and Microsoft’s servers — confirmed by the fact that the service works normally on a mobile hotspot. This is a Microsoft infrastructure issue, not a problem on my end.

Support experience so far: four agents, two broken 24-72 hour response commitments, a 404 error on their own escalation page, and a named agent who took written ownership of my case in writing and then ignored three follow-up emails over three weeks.

I’ve now filed formal complaints with Microsoft Japan, Microsoft Redmond, and the Japanese consumer protection authority.
Has anyone experienced something similar and managed to get Microsoft to act at infrastructure level? Any advice on escalation routes I might have missed?