+1 on the eigenchris stuff. They start a little rough as he’s still learning how to present online, but improve quickly, and he has that knack for explaining things clearly that some people seem to be born with.
Second this one, I remember being enthralled in undergrad just going through these lectures. I should give it another watch through since there was a lot I didn't understand the first go around
Osgood is such an engaging lecturer and his explanations are crystal clear.
Eigenchris' youtube series on tensors is great https://www.youtube.com/playlist?list=PLJHszsWbB6hrkmmq57lX8...
He also has video series on Tensor calculus, General Relativity and a few other topics. Its an incredible labor of love.