Ubuntu VM in Truenas Scale very slow network performance

I’m pretty new to Truenas Scale but so far I’ve solved all of my issues up to now with the help of the forums and help posts so thank you so far!

This is where I’ve got stuck - I’ve got an Ubuntu VM set up inside Scale but the network performance is hopelessly poor. It does connect but it can’t even update apt without loads of errors. I only have one Ethernet port on my machine otherwise I would have tried to pass through a separate device. I have tried VirtIO and Intel, neither made any difference. I also tried to set up a bridge device but when I tried to follow the guidance, I ended up disconnecting from LAN and I had to connect up a GPU and sort that mess out.

I’ve done a lot of searching and I can’t find anything to solve my issue yet. To be honest, I’m trying to keep everything simple, so if there’s a simple answer that’s the one I’m looking for.

My main questions:
How can I check why the VM network performance is so poor?
Should the VM be able to “share” the single connection without an issue?
If not, is there a way I can split it in software, or do I need to add another ethernet?

PS. my mobo also has built-in wifi which I considered passing through as an extra connection but I can’t pass that through because my CPU doesn’t support ACS, so that was a non-starter as well.

I think I solved it so I posted too early! It was obvious really… my pihole was running on the truenas and so it was looking for the truenas for DNS lookup but couldn’t access it, so all internet wasn’t working but actually network was fine. Changed DNS for DHCP temporarily to router, all working again.