Mac Unlock by Apple Watch only Works Sometimes

I have my Mac (M1 Mac Studio - OS Sonoma 14.6.1) set up to unlock with my Apple Watch (Series 9 with latest OS). It worked great in the past but for the last few weeks it has been very unreliable. It will work a few times then just stop for days. It works about 20% of the time at best. When it fails only the password prompt appears on the Mac, nothing about the Apple Watch. They are on the same WiFi and the same Apple ID. There are no discernible changes between when it works and when it doesn't. I tried unpairing and re-pairing my watch from my iPhone a few weeks ago and that worked for a week or so before back to the same thing. Any thoughts or suggestions? Thank you