From this article, we can see that the entire path, including the file name, must contain fewer than 400 characters for OneDrive, OneDrive for Business and SharePoint Online.s, and SharePoint
For users but not Msft? As I said above, the url giving me the error has 536 characters, which is pretty small compared to many system generated urls. Msft can't have it both ways - there's obviously no reason why a site template fails because of the url length, that's nonsense.