Replace TeX by T<span class=\"e\">e</span>X: possible?

[dbitouze]

Sorry if I don't ask at the right place and if some of my questions are very naïve but I'd like to know before I start to (try to) understand how this machinery works. Is it possible with (a) markdown-it-py (plugin):

1. to make replacement without Javascript? I mean that the replacement is done only during the HTML build process by Sphinx.
2. to replace TeX by T<span class=\"e\">e</span>X during the HTML build process by Sphinx? Here I mean just “TeX“, delimited by spaces or start of line or end of line, and without using any other marker.
3. in the previous case, for “TeX“ in inline blocs and in code blocks to automatically not be replaced?

If so a tiny template as a starting point would be very welcome!