Is there a playable version of the srb2 2.2 9-14-2019 Prototype?

I'm just a fan of the tracks, especially RVZ1.

Probably not but im sure the developer who did the music could still have it .

The Lach reaction video one? I asked Sev about the build, but he didn't reply so I take it as a no.

During 2.2 development, maps were worked on separately by level designers in individual WADs, and it was only in the few months leading up to release that those assets were compiled into "betas", so that developers could play through all the content in one run. "Beta 6" just happened to be the current compilation at the time I joined STJr, and it was recorded because it was one of the only chances developers would get to see a playtest of the game from a veteran player before release. We don't have them available for download.

The RVZ1 track in that video is just the version from CobaltBW's Music Remade mod from 2.1.