If you have an eGPU connected (to your Mac) you can, as far as I know, prioritise what should run on the eGPU(s) and what should be processed on the internal GPU. If you find Blender in the Finder, in Applications, and right click, select "Information", the option "Prefer external GPU" will be suggested (but only if you have your eGPU connected). This will allow you (whatever you are doing) to continue your work.

Hope could help
If not, there: "https://support.apple.com/de-ch..."

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