Some youtubers don’s show their face and have no substitute for it. Others have small animated characters and some basic lip-sync when they are talking. If you’ll be using an interactive pen display, like ones from Wacom, for your educational videos, your face would only be an obstacle for viewers anyways and you shouldn’t be penalized for it. Make sure you make up for the missing “personal connection with user”, that comes from eye contact, with high quality video production, especially the sound has to be 10/10, no skimping on the mic. If you voice is not radio-sounding, or you have thick accent, text-to speech software is probably best and cheapest way to start.