Thanks @florent - I can see some of the export logs, but not this particular window-vm, unfortunately. Probably because its too far back in time:
Dec 27 21:33:19 xoa xo-server[845]: 2025-12-27T21:33:19.667Z xo:vmware-explorer:esxi INFO nbdkit logs of [datastore2] DEBIAN 11 observium.iextreme.org/DEBIAN 11 observium.iextreme.org.vmdk are in /tmp/xo-serverG5cHF7
Dec 27 21:36:22 xoa xo-server[845]: 2025-12-27T21:36:22.559Z xo:vmware-explorer:esxi INFO nbdkit logs of [datastore2] Windows Server 2022 veeam2.iextreme.org/Windows Server 2022 veeam2.iextreme.org-000005.vmdk are in /tmp/xo-serverqv0XVK
Dec 28 00:32:35 xoa xo-server[845]: 2025-12-28T00:32:35.287Z xo:vmware-explorer:esxi INFO nbdkit logs of [datastore2] DEBIAN 11 observium.iextreme.org/DEBIAN 11 observium.iextreme.org.vmdk are in /tmp/xo-serverfqb8lP
Dec 28 15:28:09 xoa xo-server[845]: 2025-12-28T15:28:09.050Z xo:vmware-explorer:esxi INFO nbdkit logs of [datastore2] DEBIAN 11 observium.iextreme.org/DEBIAN 11 observium.iextreme.org.vmdk are in /tmp/xo-serverxcV6N7
Dec 29 20:13:27 xoa xo-server[845]: 2025-12-29T20:13:27.226Z xo:vmware-explorer:esxi INFO nbdkit logs of [datastore2] DEBIAN 11 observium.iextreme.org/DEBIAN 11 observium.iextreme.org.vmdk are in /tmp/xo-servermnF0TD
The observium VM worked at last, but I had to give it 4 tries before it actually worked.
Edit: Right now all my important VM's have been imported, so I don't think we have to spend anymore time on this, unless you want the logs for the observium import.