While I was reading this post couple of ideas crossed my mind.
I don't know if it would be your cup of tea, but here it is...

1) Udemy - it's a site where you can post/create all sorts of courses. As far as I know, it's possible to become one of the instructors there for free and create your own course.
Although most of the courses are some kind of video courses, there are some others too that are not (e.g. created as PowerPoint presentations or else).
However, if you already didn't come across that site, you may see how others are doing it there, as there are some free to take courses as well.
Maybe you can start with the following one - Online Course Creation - just to take a look.

2) Regarding your wish to teach English. Here is my a bit out-of-box thinking about it. For instance, and although I'm not an Asian descent, personally, I would like to learn English better as it's not my first language.
But, the way I would like to learn it's kinda different.
For example, it would be a huge help for me as here on Steemit, same elsewhere, if someone would proofread my articles before I publish them.
I know I can go to Fiverr or some other site out there where I could order a proofread and case closed.
But what I want is not pure proofread, it's proofread with lessons or teaching why something should be put this way or another. I would like to know and understand that.
I don't know if anyone is doing something like that, but that's something I would be very interested in.

So, that would be my 2 cents answers on your questions. I hope, if nothing else, at least it might give you some new idea.