I had some experience setting up an eGPU on a normal Linux laptop before, using that wiki. When trying it on BANSHEE, it has a pretty similar setup, with one catch: you need to manually set the relevant type-c port into TBT mode using ectool for the GPU to be detected (assuming you already have the modprobe type-c service running).
Other than that, you’ll do just fine by following the guide on how to get normal Linux laptop connect to an eGPU (e.g. by using a switching script like GitHub - dangreco/gnome-egpu: eGPU switcher for GNOME using udev rules)