(These are some of the finest educational materials for mathematics that have ever been created in any media, they really are that good.)
The gap which I'm trying to fill here is that 3b1b goes over the higher level intuitions but tends to skip over some of the details at times (which is fair enough, they're a pain to demonstrate through video and animation). The idea I had here was to have worked examples as well.
Different tastes for different people. I found this website to be more useful, since I can browse, reread and skim through the text much more easily/faster than on video.