A pixel 6 with graphene OS - how to enable Text-to-speech ?

Hello all,

I've got a pixel 6 with the Graphene OS on it, and would like to be able to
use the text-to-speech feature.   When I try to use it (from within my ebook
reader) it shows "waiting for TTS", "failed TTS" and than retries a couple
of times before throwing the towel.

I have no idea if its just a question of enabeling such a TTS component, or
if I need to download-and-install one.

I the former case, where should I be looking for the settings ? (found a few
suggestions, but didn't find any TTS component related entries)

In the latter case, suggestions to (a good) one would be appreciated.  The
fewer permissions needed the better (requiring permissions like "internet"
means instant rejection).

Regards,
Rudy Wieser