IMHO Intel ME or the AMD equivalent are only relevant for state level targeted attacks. It wouldn't be wise for them to waste it on the small fries and risk having some snoopy I-have-nothing-better-to-do-with-my-life security researcher find some attack payloads.

Of course you are right to be worried and think about it. Right now the best you can do is coreboot, it allows you to disable it.

If you want to counter that risk the best is to get a computer like the nitropads (coreboot and only open source firmware, qubeos on top) https://www.nitrokey.com/news/2020/nitropad-secure-laptop-unique-tamper-detection or the ones of system76 After that, it's no use worrying too much. You could as well be hit be hit in a car crash, a seism or a tsunami could also hit you city. Don't think about it too much, just have a small plan so you are not too lost if the black swan comes for you.

I think that a lot of the IntelME stuff is what people would typically call a conspiracy theory, not like a theory of a conspiracy, but rather where the conspiracy is largely invented for the purpose of being scared or angry, or for attention from others who get scared or angry. Obviously not all of it is, and there are people who do research it, but the videos about it that you usually see on YouTube, most of them are like this.

The thing is that intelME isn't like a government conspiracy where there isn't much if any tangible evidence for it, IntelME is physically installed on millions upon millions of Intel PCs around the world, so it's very easy to test the myths and claims by sacrificing some of these Intel computers. The fact though that most of the people making claims seem to not want to do that, suggests that they don't think it's as big a problem as they say it is. There are few people who have tested it though, a notable example from 34C3 where they found that it's actually much more boring. Honestly the idea that people say it cracks Wifi passwords, or exchanges data home with a server, all this stuff people claim can be easily tested, even analyzing the network packets from a PC to see if it actually phones home when it's off (can do that by probing an Ethernet cable and capturing the signals externally. The reason I claim the IntelME stiff is a conspiracy is because most of the people making the claims resist investigation, the same way that Flat earth theories and Lizard people theories resist investigation. My example of probing the network cable? Yeah I proposed that to someone already and they claimed IntelME would know the Ethernet is being probed, when I inquired how I was given many nonsensical claims, from microphone listening to talking to IntelME on another computer skewing the results, can't make this shit up.

So to summarize, a lot of the claims are unsubstantiated claims, which could be easily proven or disproven due to easy access to IntelME based systems, but isn't because the people making the claims can't be bothered, and to top it all off many of them simply make arguments to resist investigation of IntelME in the first place, just like classical bad-faith conspiracy theories, and actual investigations like the one shown as 34C3 are swept under the rug. I don't think IntelME doesn't have issues or that it isn't a security risk, it is like any firmware, but the sensationalized claims made about it regularly online don't hold water, and the people making them should be called out for perpetrating conspiracy theories without merit. I'd leave some links to them but I don't know if that's allowed here, could be considered harassment.

I choose not to think about it or include it in my mental threat model, the same way I choose to not worry about thermonuclear warheads.

If there’s some exploitable backdoor and Intel gets owned, we’re all boned and there’s nothing we can really do about it. I don’t have anti-ballistic-missile systems, and I also don’t have the capability to make an entire hardware/firmware/os from scratch.

So instead focus on the things you can control and are more likely to happen. Don’t plan for doomsday, plan for every day.

Anything that was designed be exploited was designed that way for a reason. You think Intel isn't aware of the security issues with how they designed their CPUs?

It is a huge threat just like any low level firmware. However, there isn't much you can do

The NSA tries incredibly hard to not make public which of the many many options in their toolbox are in active use at any given time. Not sure anyone outside the org can say for sure what they are and aren't using.