I have no influence on the display size within a VM.

The initial situation: MacOS Monterey is running on the base machine. A 4K screen (40 inch) with a basic resolution of 3840x2160 is connected, but this has been reduced to 2560x1440 via a system setting. Another macOS Mojave was installed in a VM using Parallels Desktop 17. The display available within this VM is limited to 1024x768 - this is really poor and totally unacceptable. The system settings of the emulated macOS do not offer any other options. Hopefully there will be an update from Parallels soon.

 

The problem could be solved. The installation of Parallels Tools was overlooked. After completing a VM installation (on the host), it could be useful to find a note there when opening the VM for the first time that the tools still have to be installed.