Why do I get prompted for two-factor authentication on the same device?

We all know that Apple's implementation of two-factor authentication is, despite good intentions, horrendous. For me, it's gone from being a mere annoyance to downright almost ready to rid myself of Apple products. My understanding was that once a device was authenticated, it became "trusted" and would no longer invoke the two-factor auth process.

That doesn't seem to be the case.

I have an iMac, two iPads, and five iPhones in my family. Every time one of us logs in to something using our family Apple account, the two-factor authentication process gets invoked again despite the fact that we've all been using the same devices for 2+ years. EVERY TIME. At what point will these devices become trusted? I can understand it happening the first time. But there is absolutely no reason to make it a constant thing.

Apple has made sure that I can't turn it off, so I'm stuck with it.

Is there anything that I can do so that my devices become fully trusted, never invoking the two-factor authentication process again?