To change the time sync it seems that when u go to advanced settings switch off the display time stamp first, then press the sync button. After that apply the display time date button on and go back to check the time again to see if this is showing the correct local time update. You need to do the same for each individual camera. It worked for me.
You are correct that the time must be updated one camera at a time. I believe that has been a request on the Wishlist for a while. You might want to go there and vote it-they do use that as a source of improvements.
I’ve never had the need to do anything other than press the synch button on mine. If you are having a problem with that and would like to purse it further, it would help to know more about your setup:
-Phone or other Device type and OS version on phone/tablet
-Wyze Device Type and model,
-Wyze app version. (Home Screen/Account/About). Beta or Production Version
-Firmware version installed on Wyze device (Settings (gear icon top-right)/Device Info/ Firmware Version) - “latest” and “up to date” are subjective and will change as updates occur
Thanks for the workaround though!!