I've charged a Mac with the Switch cable, and a Switch with the Mac brick. Nowadays I charge everything with the same brick from a dell laptop from 2018.

Is it the most efficient? Probably not. Is it hurting the batteries of my devices? I guess?? I haven't noticed any issues with any device and that's 8 years now. Perhaps I've been lucky.

That's for charging. Data can be trickier, that's true, but often devices that use USB-C for serious stuff come with their own. Chargers from aliexpress-grade stuff I just discard to the drawer of the 1M-cables from where nothing will ever come out.