When configured to start in full screen, the client should already know the size of the screen, and it therefore shouldn't have to do a resize when starting a session. This can be seen in tlclient.log when starting a session on Windows (10 or 11), where the client has been configured to start in full screen in any of the available full-screen options. Output in tlclient.log on Windows: > 2025-06-30T14:42:35: vncviewer[E]: DesktopWindow: Reducing window size to fit on current monitor