I suggest you try a DeepPRIME export with each of your options and compare time and display refresh experience. You can change which device will be used for DeepPRIME in Preferences > Advanced > DeepPRIME acceleration.
I do not expect very good result with the hardware at your disposal though. It may still be faster than with CPU so worth a try.
As for a better GPU, in laptops it is not possible to change it to my knowledge. It may be possible to use an external GPU but I don’t know the requirements on laptop side and it’s still not officially supported by PhotoLab (not tested). This could be a feature request.
Lucas,
Are you saying that you don’t know whether an eGPU connected to a laptop will shorten DeepPRIME processing times? How about an eGPU connected via a Thunderbolt 2 to 3 adapter to my 2013 Mac Pro? I’m considering the purchase of an Akitio Node Titan for purposes of accelerating my PL4 exports.
If it works it will be faster almost for sure (supposing you put a better external GPU than the internal one of course). We just cannot guarantee at this point that it’ll work flawlessly.
eGPU through Thunderbolt 2 is not officially supported by Apple. You’d have to trick the OS to get it working. I don’t think TB2 to TB3 adapter would help.