What doesn't work? I ask, because all these downgraders do is the same thing described in various posts - the PR project file is modified to change the file version number. I changes nothing about the file structure or contents. The instructions have been posted in the past few days related to the problem in the brief, now stopped, roll-out of Release 25.6.0.
For some users the "doesn't work" is that the downgraded project opens as an empty project, or they get a "bad file" error.
I suspect that, if this is strictly related to the Beta and not the pulled 25.6.0 release, the new mask feature does something that makes the file incompatible.