Hi Komatös, thanks for your opinion and greetings to Hamburg, I live there, too
Unfortunately you are wrong, I wish you were right.
%LOCALAPPDATA% is the designated personal space for userdata that may be left with the computer and discarded in case of roaming.
%APPDATA% and "Documents" is the designated personal space for userdata that would sync to the server when roaming from computer to computer.
%ALLUSERSPROFILE% goes to %Systemdrive%:\ProgramData and is a grey area where vendors may decide how multiple users share local data.
%USERPROFILE% is the last resort, very unfortunately used by disorientated multiplatform ports, often coming from linux and I have seen quite some runtimes that lure developers into that error, (QT and what not), resulting in the same problem...
The proper way of finding the correct locations is not by using these variables, but using the API and the "Known Folders" as described here: https://learn.microsoft.com/en-us/windows/win32/shell/known-folders
(The Registry location for the personal pointers is here, btw: HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\User Shell Folders )