I've been a fairly active roleplayer/gamemaster for about 30 years now. I've also done talks about roleplaying and gamemastering for over a decade. I've considered putting up a YouTube channel, or writing a book about it. (There's about 10-12 hours of recordings of me talking about rpg things on YouTube already, but it's all in Finnish and the sound quality isn't great.)
AMA about gamemastering and I can probably help.
I also larp
I've only ever done one d&d campaign though
I started with Cyberpunk 2020 and moved on to more serious stuff. Or you know, pretentious, if you like that word.