Hi. Apparently, Valve has reverted the Steam client changes that didn't allow for native, direct downgrade.

Source: user @StepS
He posted a comment in his own Steam guide:
https://steamproxy.net/sharedfiles/filedetails/?id=1805934840

For now, DepotDownloader isn't needed anymore. Even so, you could keep it in your guide as an alternative solution, just in case.