If you liked Sheldon Brown (who was a treasure but the content is out of date now), definitely check out the Park Tool videos on YouTube. Calvin Jones, their director of education, recently retired after building an incredible library of instructional videos. As an amateur bike mechanic, I wouldn't have been able to build or maintain my bikes without Calvin's videos.
+1. I would add RJ The Bike Guy's youtube channel -- straightforward, down-to-earth, no-nonsense videos, may prove immensely useful if you have simple, traditional, cheaper-end bicycles at home, and only a basic set of tools. Excellent explainer; has similar "vibe" to Sheldon Brown's site IMO: https://www.youtube.com/channel/UCaAK2FaxQ2xiBbAUVZsvDYQ
When I very briefly worked at a bike shop even some of the pros said they basically learned everything from Park Tool's Youtube videos!
Their bike repair manual is awesome as well !