Here's more on Thinkific and other course hosting: https://forums.sitesell.com/viewtopic.php?f=27&t=219531
I'm in a similar situation to yours, Jude: lots of information I hope is helpful, good traffic and appreciative comments, but very little earned (nowhere near covering my SBI payments yet, after over 5 years.) I have two courses with Thinkific (one that's currently free, both in the last 6-8 months), and am about to launch another I hope will make a real difference. I'm quite pleased with Thinkific, as are the other SBI'ers whose comments I've read.
One possible suggestion: you mentioned having lots of information to teach. You might consider offering a short course on some key part of it as well as a comprehensive course. 2 reasons: the biggest is that some people will be overwhelmed by too much at once and will give up way before finishing, even if they buy your course and you provide all the help you can. (This is experience speaking-- even after I greatly reduced the amount I originally planned to include in my first course, and broke it into several shorter courses.)
The other reason is to get started teaching (and earning) faster, especially as you will learn so much-- things that might make it much easier to do a better comprehensive course after you are familiar with the process and have some feedback from students.
I have a brother who teaches high school and he did his best to help me keep cutting down my plans and making the individual lessons as short as humanly possible. He says you can hardly overestimate the shortness of most people's attention spans now. (I'm from a much older generation that grew up reading longer texts and can concentrate for a while-- a skill that's apparently being lost.)
Best wishes on your course and your future success!