> In a Linux context I got some GPUs working and I can add some [external] GPU devices. Minis forum when I reached out to them said they don't officially support either via the Thunderbolt compatibility USB 4, USB4 v2 or even the built-in PCIe slot. Yeah, not technically officially supported and it's because of the resource allocation and the BAR space and they need somebody on the BIOS team to understand that to fix it.
https://www.youtube.com/watch?v=TvNYpyA1ZGk
There are ways to manage BAR better in linux or with UEFI preboot environments for windows as hobbyists have been doing for ages due to bad BIOS support https://github.com/xCuri0/ReBarUEFI