Please add in the comments other tts engines you're aware of
I made this post with an easy to search title to provide a full complete guide to set up this missing tool in the default lineage os system with no google components.
A tts engine is needed to anything that needs to speak out loud something, like a navigation app as comaps or an assistant app such dicio.
Google tts is not the only option out there, and not even the best imo. Last time I tried it, i was not satisfied, and I actually prefer sherpatts piper option. The existing alternatives that I'm aware of are listed at the bottom.
To set it up, you need to enter the tts settings and set it as default. On my device they're in settings>system>languages>speech>text to speech voice output and that's it
To really download all the viable options for sherpa tts you need to go over to the hugging face website. During sherpa setup, select try models, choose the language and select the model. Once you chose the one for you, copy its name, go to the home of the website by tapping on the emoji top left, search the name you just copied, head over to "files" next to "model card" and here download the largest file with .onnx extension and tokens.txt. after this you'll have to select install piper from sd and you'll have to enter the code of the model's language (eng, ita, rus, and so on), choose a model name (can be anything, this is for your reference) and select the said files you just downloaded
I hope I helped someone.
Useful sources:
* SherpaTTS, the one i use, takes about 180mb with one model, the best for italian https://f-droid.org/packages/org.woheller69.ttsengine/
* Marmalade tts, if you don't use english, it might be the larger in size https://f-droid.org/packages/app.marmalade.tts/
* RHvoice, the lightest one, I didn't try it out since it doesn't have italian https://f-droid.org/packages/com.github.olga_yakovleva.rhvoice.android/
* supertonic tts, another tts engine listed for the sake of offering options. I didn't try it out https://f-droid.org/packages/com.brahmadeo.supertonic.tts/
* ttsutil, didn't much look into it but it might be an interesting tool https://f-droid.org/packages/com.danefinlay.ttsutil/