In short, the Intel Management Engine and AMD Platform Security Processor, which are on many motherboards, allow for remote power on and remote control of a PC if connected to Ethernet, are closed source and have known vulnerabilities.[1] This website has a more elaborate explanation: https://libreboot.org/faq.html#intel [1]: https://www.intel.com/content/www/us/en/architecture-and-tec...

If you ever do something revolutionary that would upset the apple cart, yes: you do need to be worried about this. Its a computer, within your computer, which you do not control - and it can be used for any secret purpose your enemies may desire.

Don't have any enemies? Well then, you've got nothing to fear. But lets say you do something big, which will change society, perhaps disrupt an existing American Military-Industrial player .. well then, that small component is going to keep you down, brother.

If the machine has two network interfaces, the management engine will only be active on one of them (always the lower numbered interface). If you don't need both, disable NIC #1 and only use NIC #2.

You will get the benefits of the management engine without any external exposure.