For anyone else that is interested in this question: I've tried a whole bunch of the TTS services and found that Microsoft and AWS are the best of the standard providers IMHO and these are services that tend to have startup credits available so I use a mix of these two - I try to never rely on just one provider. I've met with the Eleven Labs folks and some of their demo's of the V2 stuff that's coming are really amazing but latency and pricing might rule them out as an option for the time being.