Yeah, he also did some excellent YouTube videos and tutorials which helped me get into i3 and mutt, but I find it hard to recommend them now because they're mixed in on his channel with some weird ranty videos that, at best, don't have much to do with tech.
I still recommend mutt Wizard though because it makes it so much easier to get everything set up. I feel like it should be absorbed into neomutt or similar because it feels like such a basic thing to get right.