I don't think BIOS/UEFI can do power-on timer unless it's server-class hardware? Have not looked into PC BIOS/UEFI for a while.

For failsafe, KVM might be the ultimate solution in case boot got stuck.

I don't know about UEFI - I don't have any UEFI system - but my Gigabyte 880GA motherboard can certainly do RTC power-on from BIOS settings and it's far from being a server motherboard.