Electrician 100% and it’s really fun too.
I’m a software dev and that would be my backup trade as it scratches every intellectual itch if you work on more complex setups as well as mechanical fulfillment as you actually see your work published. The community is huge and the demand will almost never decline. The only downside that it’s not very mobile but still much more mobile than most other trades.
My friend is a locksmith and if your area is not overcrowded and you can keep a good company running it’s really good. People pay a lot of money to get back into their car at 6am but also every building needs a lock and the locks need maintenance.
It’s a real business though as the trade aspect of cutting a key or opening a door isn’t difficult at all. The challenge is running business, accounting and all the certifications and associated protocols. With all that said, it can get crowded real fast so this all only works if you’re one of 3 locksmiths in town at most.