anyway in bhyve to set the uefi bootrom to pxe boot?

I can't recall the details now of the rom image we use, but IIRC in theory (at least), there should be a file that basically acts as the VM's nvram -- if you think about a physical system, where it persists all the stuff in the setup

for UEFI, that should include UEFI variables

which would include all the bits for managing boot order

but I can't recall seeing anything when the VM starts to go into setup, nor do we have anything I'm aware of that'd let you manipulate those bits external to the VM

(e.g. create a Boot#### variable for PXE boot on whatever nic, then stick it first in the BootOrder variable)

with loader, in ok prompt, enter: reboot -f

but for actual pxe boot, you probably need pxe firmware or such, perhaps something like chainloading ipxe..