My advice is to start using what you already have, like your phone. Get a small cheap tripod for it to hold it steady and use that.
There are two reasons for this. First is that people want good content, and don't really care as much about the quality of the video and audio. Plenty of popular YouTube videos are shot on phone cameras. It would be a shame to spend so much money on pro-level AV equipment only to find that you don't actually have the time, skills or patience to properly plan, record, re-record and edit videos. It would be better to use what you have until you get into the swing of things, and by then if your equipment is lacking, you will know exactly what features you want when looking for something new. After all, today's mid-level phones offer video quality that can be better than prosumer equipment was a decade ago.
Second, it's not until you start using the equipment regularly that you realise what you need. Maybe your environment causes the autofocus to hunt a lot, or there's background noise the mic picks up, or it takes forever to transfer the videos to your computer for editing. You don't want to have bought something that is specialised for someone else's environment only to find it doesn't have the features you need in yours. If you're fairly static in a teaching scenario then you might favour a camera that can be quickly locked into manual focus, whereas if you're walking around looking at different things you may want to pay extra for a faster, higher quality autofocus mechanism. You won't really know until you start producing videos so in my opinion it's best not to rush in to buying something until it has become clear to you that what you already have isn't meeting your requirements.
Who knows, you might find like a lot of YouTubers, that your phone on a tripod is perfectly fine already.
It's probably best to think of it as though the equipment you use for your first few videos will need to be replaced once you know what you're doing, so you might as well use something cheap (or free, if you already own it) for that. No point buying expensive stuff to start off with if you know you'll have to replace it a few months later when you know what you really want.