Security tunnel vision?

I am window shopping for Linux laptops. Lenovo Thinkpads are a popular choice because of the ability to run Libreboot on certain processors. But is Intel Management Engine really the biggest threat? In my former job (many years ago now), I was involved with IT security. At the time, Lenovo laptops were essentially banned from certain govt facilities. There were whispers about things like undocumented circuits concealed within multi-layer circuit boards. I suppose binary blobs could also have been an issue.

Years have now passed, but the suspicion remains. Recently, the US state of Georgia has banned Lenovo from state purchasing. https://finance.gatech.edu/2025-07/lenovo-statewide-contracts-suspended

So it is a bit ironic that Thinkpad T480 laptops, which are now popular as Libreboot machines, would be banned by government authorities as a security threat. Are proponents of Libreboot suffering from tunnel vision in thinking that used Lenovo machines are fine, but US-made machines are bad because of Intel Management Engine? What do you think?