Revanced won’t be able to install, but you could still install manually the apk it creates. That’s what I do (not through adb though).

Don’t call it sideloading. Did you watch the video?

You’re absolutely right!

https://fightchatcontrol.eu/

What do you mean “dying”? Facebook and Instagram are absolutely the dominant social networks / apps in most of the world. Sure there are insane amounts of bots, trolls, scammers and manipulators, but that doesn’t make a platform “dying” while billions of people still use it.

I’ve had my account for over a decade, so I’m not really up to date with the current process. There used to be a period when you couldn’t just sign up (I think it was invite only?)

I can see this app you mentioned on mobilism.org. You need an account to get to the forum though, and I don’t know if they’re open to signups.

With DEX you can use your phone as a touchpad.