NTT v10000+ is a beta branch on steam (ntt_development), u just install that branch then launch via the steam play button.
the sound being messed up in v9944 is something that happens when it's installed incorrectly (it's a weird setup process), id recommend looking at the setup video thats in the nt discord.
both v9944 and v10000 are supported, u should use whatever runs better for you (or v9944 if u wanna play alongside NTTE)