No deep sleep tracked since WatchOS 26 update

I have been using Apple Watch to track my sleep with my most recent watching being a Series 9. Everything was fine until the last upgrade to WatchOS 26. Now it no longer tracks deep sleep, which was typically 45 minutes a night over the past few years, but is now tracked as 0 to 5 minutes a night. I am tracking it in the Health app.

I even tried sleeping for a few nights with a Fitbit to check things, but it shows the same sleep breakdown as always, so nothing seemingly has changed with me. The only commonality I can see is the watch and phone software upgrades as that is the exact night things went off the rails.

I’ve tried restarts and such, but no luck so far. Open to any suggestions.