Not exactly sure of your use case, but maybe this cpuld work for you. I have a testbed workstation that i crash sometimes. I put the power on a shelly plug, bios set to power on after ac loss.

Problem is- how do I enter the disk encyption password remotely? And more importantly, how do i do it cheaply?

https://github.com/tobiaas/esp32-web-keyboard

I just adjusted the wifi config to join my network instead of broadcasting an AP.