Please consider adding a little bit of javascript to find and display the text that describes the variable in a formula when the mouse hovers over it. Even better would be to allow signed-in users (or paid subscribers) to add annotations (and links to youtube videos).
I would prefer if your site requires a paid subscription so you can incentivize people to annotate the content. For a paper author, making the paper terse and complex is more impressive but for the rest of us it is very tedious to decipher.
You can check out a similar site here, for example
https://academ.us/article/2202.04668/
If you click on the cross reference of figures and equations it will pop up a sticker showing the corresponding content, if that's what you mean.
I would prefer if your site requires a paid subscription so you can incentivize people to annotate the content. For a paper author, making the paper terse and complex is more impressive but for the rest of us it is very tedious to decipher.