If you have the funds, donate to Mozilla. They're not only the main developers of the only major competing browser engine, but also do a lot of other good work. You can hope for others, but with Firefox only having single-digit usage share it needs all the help it can get.

Did you consider becoming a whistleblower?

I've been on 4-5 MVNOs with Pixel phones. Am I just lucky, or does Google not allow these shenanigans?

Didn't RTA.

They absolutely would've been able to grandfather users that paid before the subscription was added. Pure greed and they know you can't do anything about it aside from leaving a bad review.

How are kilts any different from boxers or, like, most other clothing? I don't think I've ever crushed my balls sitting down.

I've never been unable to access a site on Firefox due to DRM. There is a prompt asking to run DRM-enabled media, but that's it.

Edit: or is there something about Manifest v3 that will get Firefox blocked somehow? IDK how as I would think it would be easy to pretend to be compliant.

Google has two a year, right? One high-end, one mid-range. Supporting both is probably not much more effort than a single model.