May I recommend: lesser known org-modes

This mode adds numbering to headings. Like this:

* 1 heading
** 1.1 subheading
*** 1.1.1 subsubheading
** 1.2 subheading
* 2 heading

This is not added to the text directly, only visually. I believe it is done via overlays.

This mode converts some TeX markup into the respective UTF-8 symbols, visually (as prettify-mode does). You can get a list of all available entities(symbols) using org-entities-help. BTW, it is also possible to define your own in org-entities-user.

So to give you an idea how of how it looks,

1_1 a_b^q q_p p^q

Gets prettified into,

Some of you might be wondering, "Why would I use this when I have org-preview?". This is much simpler for when you just need to type a symbol.

Another potential question could be "Why wouldn't I just C-x 8 RET (insert UTF-8 character, for those who are not aware)?", you can't do a superscript q or subscript q, since those symbols don't exist! Which is why I chose q for my demo above.

Also this is way more convenient than C-x 8 RET, and that reminds me, there is a similar feature to this which actually inserts UTF-8 characters into your buffers, C-x RET C-\ TeX RET. Then you just type the TeX markup as you normally would, and it inserts the actual symbols, but this too has the same problems as with directly inserting symbols, some symbols are simply not available.

As a side note: I am sick of having a Unicode character for ☃ and ⛄ but not a superscript and/or subscript for half the letters! Why???

Thankfully, I can just use this mode and type all the q_q^q I want. Also, org automatically exports it correctly when exporting to HTML!