I couldn't believe they would block about:config just like that. That mindset is completely unacceptable.
But it seems to be a bit more complicated. See https://www.reddit.com/r/firefox/comments/i51k0q/mozilla_cou.... about:config is not blocked just because of configurability and the usual danger of breaking something, but because it is essentially broken. Still, it's the wrong decision. Users can just reinstall if the app breaks, and there is no blame on Mozilla in that if they showed a warning before, as they do on the desktop.
It's not essentially broken though, because you can toggle the settings I know of perfectly fine without breaking anything.
Yes, theoretically you can break the connection between Firefox and GeckoView but that's got nothing to do with enabling eSNI or setting the behaviour of user installed certificates.
But it seems to be a bit more complicated. See https://www.reddit.com/r/firefox/comments/i51k0q/mozilla_cou.... about:config is not blocked just because of configurability and the usual danger of breaking something, but because it is essentially broken. Still, it's the wrong decision. Users can just reinstall if the app breaks, and there is no blame on Mozilla in that if they showed a warning before, as they do on the desktop.