Ok. so I got that 10Gtek and plugged it in but having the same issue, it’s seen by ESXi but no driver is loaded.
I saw a kernel warning yesterday regarding the NIC’s about BAR. Doing some digging it looks like the MMIO is being mapped outside the first 4Gb of memory, this means it ESXi can’t use it.
Usually in the BIOS there’s an option to limit PCI device mapping to the first 4Gb, but the NUC doesn’t have this option in its silly visual bios.
So it looks like I’m out of luck.
3 x520 cards and all of them can be seen on the PCI but but ESXi will not use any of them.