I'm just saying that my guess is that this probably has nothing to do with your ISP or net neutrality, and more with technical limits of wireless connections. But I could of course be wrong... Try it with ethernet and see how it goes, I just have a long cable I temporarily run through the room when I wanna play :-)
(And yeah, I think it's kinda fishy that they don't make it clearer if/that wired connections can make big improvements. Look around the subreddits about these services, or their support pages and you'll see that people recommend ethernet, and the vendors first recommendation when having trouble is to use wired ethernet [0], [1])
[0]: https://support.google.com/stadia/answer/9595943?hl=en&ref_t... [1]: https://nvidia.custhelp.com/app/answers/detail/a_id/4504/