No need to worry what's going on.... You have version 20 coming, that should simply further reassure you that Vegas is here to stay with strong continuous development and improvements !
We don't really know until Vegas team tells us. Last year it was Gary saying in a video they were moving to a continual delivery model, and it sounded like no more discreet versions, but we'll find out soon!
On June 29 MAGIX started advertising VEGAS 20 by email (sender VEGAS Post 20 / news@letter.magix.com) and at the Online Shop of the vegascreativesoftware.com product pages.
@VidGuy73991, I have VEGAS Pro 14 through 19 running on Windows 11 right now. All are running fine. Didn't figure a need to go back farther than that...