Yeah, there’s a guide for the VM approach.
Hopefully, someone with more app experience will jump in with better advice on what to put for the integration URL, or if inter-app communication requires a bridge.
On a side note, for the best results with the HAOS VM, you’ll still need to set up a bridge for Home Assistant’s device discovery feature to work correctly. For setting up the bridge, I was not able to quickly find the procedure in the official TrueNAS documentation, but here is a link to a Lawrance Systems video on the subject