I did not find just moving the drives to work. There were some other issues that I came across that might have a part to play in it, I made the lvm and filesystem on an RPI5 running OMV and moved it to a rock3c running OMV from an armbian install. Turns out there’s a pagefile size mismatch between the two that prevented mounting the btrfs filesystem. But I still wasn’t able to get the rock3c to recognize the VG or that there were new PVs attached without exporting first. So perhaps the armbian install isn’t modern enough to automatically recognize it.

I didn’t expect learning new things about btrfs to be the outcome of this little experiment, but I guess that’s just how things work.