>I've seen NEC violations galore and general bad practices on some of the larger DIY/contractor channels.

For an example more relevant to the IT crowd here: Linus Tech Tips and pretty much all their videos concerning "upgrading" a house, car, boat, etc. are rife with regulatory violations, safety guideline violations, industry standard violations, and the kitchen sink.

So if you want to learn any of the trades, even just superficially for hobby/DIY purposes, find someone who really knows what they're doing and ask them to teach you.