I just want to make sure cause it is pricey for me.
I suspect you might be confusing the restriction of two vocal tracks in the free editor with unlimited vocal tracks in the Studio version.
The Studio version doesn’t get you more free voice libraries that the free version of SynthV - it just gives you more tracks you can edit.
Any “free” voice can also be used in the free version of SynthV.
Any commercial voice libraries still have to be purchased separately.