I don’t have spare peripherals like a monitor and a keyboard. How do you suggest I do a bare-metal install of Debian on a computer (meant to be a server)?
Putting a simple preseed file on a debian install image is probably going to be your best bet. Assuming you can run a VM on your current machine it shouldn’t be too difficult to test it until you’re happy with it.
example preseed file which I use to provision new servers (VMs)