Moving from that port which was only giving 10FDx to an unused port, gave us 1000FDx.
I'm not sure where this issue stems from..
Got it sorted out, for some reason (and I'm still working on the specifics) our ESXi hosts secondary NIC keeps falling to 10FDx (likely some misconfiguration at setup).
I've moved XO off of this nic, and performance has been fixed.
If you want to improve ESXi performance, install KVM.
Yea, that's a different conversation entirely, I do want a outside of the XCP-ng pool environment, in case something goes sideways. I'm dealing with some sunkcost conversations about it, though I am making progress.