Maybe I should have worded things a bit differently. The 5 second snippets are for style transfer. I think it only picks up on the frequency spectrum of a new voice and knows how to handle that because it's been trained with several other voices. I suppose one or two sentences aren't enough to get the pacing right and all the disctinct features of a human speaker. I didn't get good results anyways. Tools like that from ElevenLabs recommend you upload 30mins to 3hours of speech.

I've managed to get the TTS running. the German thorsten/tacotron2-DDC is very good in my opinion. Could be the thing I was looking for. It just gets all the abbreviations and names wrong but the flow of the voice is quite good. And it's fast, even on my laptop. Sadly I also read that Coqui-AI are shutting down. Seems to be difficult to compete against the big-tech companies who integrate their proprietary TTS tech for free into the platforms.

I agree. Packaging and integration are some of the most important aspects if you want to actually use something. A research project is also nice, but those don't solve my every-day tasks. And I can't maintain too many development environments with complex dependencies and copy-and-paste everything to the command line. It abolutely needs to be available on the platform and there needs to be a wrapper that integrates it into the other software I use. We have that for espeak, flite and all the old-fashioned tools. But it's completely missing for the last 5 years of technological advancements...