https://bugs.winehq.org/show_bug.cgi?id=45626
--- Comment #1 from Rastafabi f.platte@platte-web.de --- If this does help anybody:
The status of the eGPU setting can be read here:
defaults read -app <app path> GPUSelectionPolicy
The command does "fail", if the setting hasn't been altered previously, so it's safe to assume, that "prefer eGPU" hasn't been selected. Enabling it does not affect the system if there is no eGPU present.