Don't get me wrong, I think Lineage is great and I use it too, but I think too many people are fooling themselves on how much extra security they're getting using it.

LineageOS will be using the exact same baseband that came with Android 9 on hardware they're deploying Android 12 to, if the phone's actual support stopped at 9. Yes with the new "Play System Updates" there's better security coverage, but it's still a gap compared to supported hardware.