Very interesting article! A big part of the outlined techniques I also kind of discovered by trial and error.
I recently also started to work more on my math skills and putting in the mathjax was getting very time consuming. To reduce that bottleneck I can recommend this small app: https://mathpix.com
PS: I stumbled once over this collection of proofs without words and they make great Anki cards to build up intuition: https://mathoverflow.net/questions/8846/proofs-without-words
thank you! This is amazing. I wish I’d known about this sooner.