FilipNest:
As far as software, which was not your question :
and rather than reposting, here are links to three posts i’ve made on this. ( I may have made other posts too. )
The Evolution of Yamaha's Vocaloid - #7 by Jukka
Music Synthesizer Technologies made using AI Methods - #21 by Jukka
CT-S1000V, singing synth from Casio - #96 by Jukka
Also look for newer AI stuff too, i’m pretty sure it’s either new or on the way.
More hardware for it is probable but i don’t know of anything specific.
I would look for a follow on from Casio as for instance.
With the price on the Casio CT-S1000V seems like a place to start, despite you keyboard aversions.
Watch the Benn Jordan video if you are interested but on the fence.
Oh and you are not forced to use an app with the CT-S1000V.