Motion detection doesn't pick up UPS or Fedex drivers

I've seen a few older posts and they also mention this but speculate about jamming, which I don't see as particularly likely due to the fact that devices just on the other side of the wall continue to work. Yesterday I had a UPS package delivery and got no motion detection notice. I did get one shortly after when I went outside to pick it up. This morning it happened again with a Fedex delivery. I also know the camera was working as I was able to switch to live shortly after hearing them drop the package. It _does_ pick up motion every day when the postal worker comes to deliver our mail. I turned off human detection to see if that was the issue (maybe UPS was blending in with leaves ?) but no luck. Now I get motion alerts for the bushes blowing in heavy wind but not for the Fedex driver. What gives? I've been looking at the spotlight and floodlight cams for other areas in my house, but if I can't trust them to actually capture motion, it seems I'm paying hundreds of dollars for security theatre instead of a reliable source of capturing footage.