Let’s try to stay in topic.
Are hardware backdoors technically possible? Yes.
Are they widespread? Probably not, we do not have much evidence of that without physically tampering a device.
How likely is they will occur comparing to other software exploits? Probably not so much because it’s way simpler to hack you remotely with some exploit or 0day or using some other traditional methods.
Totalitarian regimes don’t need them to spy and track you, they already can.