Software Stack:
ScreenFlow for recording/editing. iMovie is garbage. ScreenFlow has a really robust set of keyboard shortcuts that makes editing easy. It's also very explicitly built for screencasts, exactly what it sounds like you want to accomplish. I tried starting with imovie to be cheap but the tool is just awful.
Google Slides (of all things) for generating very basic images/video thumbnails
OBS for any live streaming.
Physical Recording Tools:
- Blue Yeti mic (can be anything though)
- iphone XS Max + tripod + white wall (to record things that look more like talks - you probably don't need this)
Happy to answer any questions. Have been meaning to put together a basic how-to guide for a while. There are surprisingly few people talking about how to make great software screencasts.
edit: formatting