I’ll start by plugging Harvard’s free courses catalog as well as Udemy
Edit: Gonna add 2 more I remembered-
Blender - I wish I had more time to learn it, but I did start the infamous “Donut Tutorial” once!
Watch Cartoons Online - Lots of good older stuff!
No
Darn. That’s why I’m with SMPlayer; that time continuity is extremely helpful to the point of being a requirement for me. VLC also has it but it actually makes the jump-to-time prompt vanish if you take too long to click it (which is… a bizarre “feature”).