Connect Mobile IOQ does not sync the steps or stairs anymore with the Venu 3. Watch is connected, sync is working but only for activities like walking

I would recommend fully removing the watch from the Connect app/Bluetooth settings and re-adding it. Here is a helpful article which should correct your sync issue:https://support.garmin.com/en-US/?faq=8CBmYmJHUr36wvJ6AktXFA 

You can also sync the watch with Garmin Express, which is only found on a person computer. You would plug the watch into the computer using the charging cable. Here is the download link: https://www.garmin.com/en-US/software/express/windows/