IIRC notifications can only be delivered reliably via Firebase — anything else gets paused if the phone is in Doze etc.
Larry Tesler, inventor of the cut, copy, and paste commands, dies at 74
{ "ok": "false" }
Sending a dump of entire system memory seems incredibly unsafe, to say the least.
Don't run sha256sum -c on your suspect file — it expects to be passed a file containing hashes and other filenames. sha256sum the iso itself instead and check by eye, or make such a hash file.
To my knowledge, symlinking a Nix file is perfectly fine (though may have interesting behavior with flakes).