What this is. We built a fully-local NotebookLM (Open Notebook) with podcast voices, then went deep finding the best Japanese voice. Most clips below read the same line from your Manaoke song so they're directly comparable.
Verdict so far: Style-BERT-VITS2 / AivisSpeech win Japanese naturalness & pitch-accent. The hunt is now for the best natural male voice β you liked JVNV-M1.