I have actually made a minor mode that does only the suscript part.
In addition it does some basic prettifying with just two commands
\alpha and \beta.   Also made a function to cycle the options.

Would you have time to look at it?  I attach the file and a test.

> Sent: Wednesday, February 10, 2021 at 7:05 AM
> From: "Emanuel Berg via Users list for the GNU Emacs text editor" <help-gnu-emacs@gnu.org>
> To: help-gnu-emacs@gnu.org
> Subject: Re: tex-mode.el
>
> Christopher Dimech wrote:
>
> > It does nothing but stops matching superscript
> > and subscript.
>
> Isn't that what you want? No match, no font lock?
>
> --
> underground experts united
> http://user.it.uu.se/~embe8573
> https://dataswamp.org/~incal
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>