Interesting question. If a binary is available you can sideload already, you’d have to put the phone in Developer Mode and use either XCode or one of the 3rd party tools for macos or Windows to install it. Main question is how easy it’d be to find a trustable official Mozilla binary.
I think that we don’t know the whole picture but if they’re canceling VPN, Relay and Monitor it’s because they’re not making enough money on those services. I also think the new CEO feels they’re spread too thin and need to focus resources on core products, which might be a good thing. They’ve gotten a lot of flak for trying different things.