etckeeper, and borg/vorta for /home
I try to be good about everything being installed in packages, even if Im the one that made the package. that means I only have to worry about backing up my local package archive. but Ive never actualy recreated a personal system from a backup, and usually end up starting from a fresh install, slowly adding back things from the backup if I missed them. this tends to cut down on cruft and no longer needed hacks and fixes. also makes for a good way to be exposed to new paradigms (desktop environments, shells, etc)
something that helps is daily notes. one file for any day Im working on my system and want to remember what a custom file, confg edit, or downloaded/created package does and why. these get saved separately and I try to remember to grep them before asking the internet
i see the benefit to snapshots, but disk space is expensive, and Im (usually) careful (enough) not to lock myself out or prevent boots. anything catastophic I have to fix is usually seen as a fun, stressful learning experience! that rarely happens anymore, for better or for worse
I played around with old iPads for a bit and then gave up. successful vendor lock for sure. I just wanted a home assistant front end without having to sign in to apple or use safari