Nah, it's encryption all right, they just back up the key in case you lose it. Which is a feature. https://aka.ms/bitlockerrecovery

I hear iMessage e2e-encrypted messages are also backed up into cloud as plaintext...

Now teach the kid about salvaging old hardware, repurposing old laptops as low-power servers. It's a lot easier to justify for a kid than the expense of buying stuff, and greener.

cd `pwd`

for when you want to stay in a dìr that gets deleted and recreated.

cat /proc/foo/exe > program
cat /proc/foo/fd/bar > file

to undelete still-running programs and files still opened in running programs

Sway. Though I graduated from Arch to NixOS, sway remains as one of the core tenets of my personhood.