While I've not used the entire Rhasspy project myself (but trying it out is on the long list of things to do :) ) I have used the offline Text-To-Speech sub-project Larynx...
...and it is amazing!
Larynx is significantly ahead in terms of quality of output & variety of voices (fifty--across multiple languages, accents & genders) of any other FLOSS Text-To-Speech project I've tried.
I think the relative new-ness of the project is part of the reason Larynx (https://github.com/rhasspy/larynx/) currently flies under the radar.
If the rest of Rhasspy is as good as Larynx I'd imagine it's worth trying out.
Larynx demo video: https://www.youtube.com/watch?v=hBmhDf8cl0k
Samples of pre-trained voices: https://rhasspy.github.io/larynx/#en-us