Best way to soundproof a single wall system?

Current party wall is about 6"/15cm thick with wooden studs and making it a thicker isn't an option in this case. Since there's no room for an air cavity, do we just double down on mass? Could we do:

5/8 Type X <> Mass Loaded Vinyl<> 5/8 Type X <> Rockwool Safe n Sound <> 5/8 Type X <> Mass Loaded Vinyl <> 5/8 Type X

Would Green Glue be worth adding to this? Do I have the order of the layering right? Should we spring for Sheetrock/SilentFX/ over typeX?

It's two living rooms being separated so the whole frequency range is in consideration, including sound from subwoofers. We're targeting an STC rating of at least 50, 60+ would be great if possible, though.

Thank you!