Firefox’s free VPN will offer 50 gigabytes of monthly data, which is pretty generous for a browser-based VPN. A Mozilla account is required to make use of it, which isn’t a hardship (they’re free), but is a point of friction some may wish to know upfront.
Not to take anything away from your overall point, which I completely agree with, but this may be a bit of a stretch. All of the “AI” buttons and features are - to my knowledge - on by default. They have made it a lot easier to change that to “off by default now and in the future”, which is very welcome, but “only opt-in” is, again, a bit of a stretch.