Why I don't see VPN button?

It's being offered in phases, so not everyone has it enabled at the same time.

If you feel like trying your luck, you can kinda skip ahead: https://support.mozilla.org/questions/1582553 but your mileage may vary.

It was said that the VPN is available throughout Canada. I already tried this flag (browser.ipProtection.enabled). It enables the VPN button, but pages don't load after enabling the VPN. I'll check this in the next version, but unfortunately many issues in Mozilla remain unfixed.

UPD. I tried this once more and now everything works. Didn't do or update anything. I'll update this thread if the problem returns.

https://support.mozilla.org/en-US/kb/unable-find-built-vpn-firefox

"It may not be available to you yet, even if you’re in one of these locations, as this is a staged rollout that takes time to reach everyone."

And while you can definitely skip ahead of the line manually, the resulting availability might still affect your experience eventually. (Please appreciate the feature is in experimental/Beta rollout phase at this moment.)