Sleep tracking stopped working for me on August 11th (tho it did pick up a nap on Aug16). Did all the basic trouble shooting. It just seems to be gone. Before that, sleep tracking worked perfectly, every night and for naps.
Classic 4 watch, Galaxy 22+ phone.
Battery has been terrible on this watch for the year-ish I've had it. Lately it's worse. Even not tracking my sleep, it goes down 40% overnight.
So I've ordered the 5Pro, should be here any day. Gave up on the Classic 4. Worst watch I've owned.