I've never seen 150 available over copper.
I've never used Stadia so I can't speak to that service specifically though. I can't see any reason why it wouldn't work any different than on Shaw.
The speed of the internet connection isn't that important. I'm on 25mbps currently where I live and I have no problems gaming. It can really depend on where the server you connect to is located as to how much latency you'll experience. For other online games I've had latency as low as 50ms to specific servers.
If you find a post useful, please give the author a "Like" or mark as an accepted solution if it solves your trouble. 🙂