I don't know but maybe this could help somebody here too, so I'm gonna share this.

I've discovered this Android app called Island, which essentially sandboxes apps by cloning them in its internal environment.

I've sandboxed that Facebook cancer app in order to keep it fucking frozen when I do not use it (I know, web version is good, but I find the app smoother).

It seems to work like a charm (better than greenify-alone ibernation, actually), but I'm still testing it.

Cheers!