Interesting, thanks for the report!

I’ve tried streaming one game too, Immortality, a year or so ago, on Game Pass, on Chrome in a recent MBP. It was fine, overall a surprisingly good experience. They said their browser streaming was "beta" at that point, and there were a few crashes, but otherwise it was fine. Not a latency sensitive game, and did very different things visually, eg filters to make sections look like old film, etc, so it’s harder to judge the quality exactly, but I didn’t notice as much in the way of over compression or artifacts as you did. Over WiFi, but I probably had a bit more downstream bandwidth than you.