I had the same problem with my 2 2019 Wyze bulbs (all of a sudden, they went offline and couldn’t reconnect even after trying for 3 hours). BUT, thanks to another community member’s helpful suggestion to go back to the older version of the Wyze app for iOS/Apple iPhone users (by joining the Beta Community and selecting to “test” the older version of the app), I was able to reconnect both bulbs within 2 minutes!!
So the problem is NOT the older bulbs, but the problem lies with the updated Wyze app!!
This was the advice I followed: