Not sure if enough has already been said about Extensions, AL, VS Code and AppSource. Probably our entire ecosystem is struggling with it and trying to find a way to move forward.
You will find many video’s here with my experiences. I’ve created plenty of extensions and tried to help a couple of larger ISV’s such as LS Retail and Continia getting started.
Take in account that the video’s are always true at the moment they are created. If any doubt just shoot me an email.