When the eGPU is re-attached, it automatically sets the external display as the primary display. If you disconnect the eGPU, your Mac defaults back to the internal graphics processors that drives the built-in display. Starting with macOS Mojave Since apps default to the GPU associated with the primary display, this option works with a variety of apps. Not all apps support eGPU acceleration check with the app's developer to learn more. Learn how to update the software on your Mac.
