Not a completed post, just notes so far.
Glycine might be the most essential amino acid we can consume. It goes so much further than I could have imagined. I read James DiNicolantonio's book on Glycine in the Spring and was absolutely blown away.
Dr. James worked with Siim Land on the book and Siim has a really informative video on it here: https://www.youtube.com/watch?v=HhPQOOhsvh0