Option to specify a default boot drive (for headless Mac)

I have a headless Mac Pro 5,1 with a NVME drive. So far works well for workstation use. Would it be possible to define a "default" boot drive in next-loader that would be chosen after some configurable time-out?

I am running the Mac Pro headless so I don't see the boot screen unless I connect a monitor and can't get to the drive selection without a keyboard.

I have done some Mac development but not sure if I could help with this.