Yes and no! It's a difficult initial process if you have no idea but becomes extremely easy once you know how PCs work.

Knowing how to diagnose problems is I feel a more difficult part. It's more complicated than knowing "These parts go there and have cables that connect to the CPU switch, main power and hard drives" because cables and parts, to a huge degree, can only fit where they belong.

I imagine in the line of PC repair work you'll encounter much more complicated issues and often multi-part damage. Also probably a lot of filth, I heard most normal people NEVER clean their PCs, change Thermal Paste or even let some nasty bugs accumulate in their PC.

Bonus points for if it's a laptop instead of a PC. Their tight compact nature makes repairing them hell I'd imagine. BONUS bonus points if you're working on an outdated PC who's parts you can't just easily swap out.