Have you considered an auto-render plugin that supports katex?

[htharoldht]

as the title says

[mitya57]

This extension supports KaTeX. Please see the “Notes” section of the README:
https://github.com/mitya57/python-markdown-math/blob/master/README.md#notes

If something does not work as expected, please be more specific.

[htharoldht]

I mean support auto-render extension, not with mathtex-script-type