Soldering and like just enough experience with an Arduino, electronics, and Ohm's law to not hurt myself.

I replaced USB ports of some DJ equipment that became unusable after a USB cable got yanked.

I clip off annoying USB lights.

Instead of throwing away my MX Master mouse I gave it another life as a backup. This involved me trying to replace the battery but completely man handling the delicate tiny port, and still make it work.

Once I got comfortable opening up the guts of electronics I also got comfortable with general repairs.

I replaced my switch joycons that got the drift.

Replaced my cracked phone screen.

Replaced the rotating clutch in my microwave.

So much more.