@glippi Hello, after swapping out the intel 82599 10 gigabit dual port and moving this to the onboard ethernet with PCI passthrough to the VM, it seems everything is stable now.
the AHCI errors, however consistent with disks (as far as I can see), it seems that in this case it was with the ethernet controller.
My guess it was just a faulty card as since moving over I have had no issues now for 18 days.
If you would like any logs, please let me know which one you would like to see for further investigation on this.