I like rsnapshot, run from a cron job at various useful intervals. backups are hardlinked and rotated so that eventually the disk usage reaches a very slowly growing steady state.

is it counting android as linux?

if so, it shouldn’t be, imo. android is deployed and used differently than Linux and is not really the same in spirit. if you can’t have root, I’d not count it as Linux for the purposes of something like this.

Funtoo is a bit of both. It’s not as current as Gentoo but the tradeoff is not having to rebuild the toolchain every few weeks.