As of the latest update of macOS 26, 26.7.1, Find My doesn't show locations for items (i.e. AirTags). Right-clicking on the item is the items list, then clicking "Directions..." doesn't work (does nothing) and Play Sound results in "AirTag Not Reachable". All this works fine on my iPhone and my iPad Pro, both running the corresponding 26.7.1 updates.
NOTE 1: Find My on all iToys works for devices.
NOTE 2: I understand that the macOS 27.0.1 has the same problem, but, of course, can't confirm that.
NOTE 3: Have tried repairing boot volume in First Aid, then from my usual account in which I'm experiencing the problem doing the following in Terminal:
sudo rm -rf ~/Library/Caches/com.apple.findmy*
sudo killall searchpartyd
sudo killall locationd
Then rebooting. Still no joy.