No alert sound with Messages
Guys and Girls, I get no alert sounds when receiving messages on my Apple watch or my iPhone. What settings should i check?
Apple Watch Series 7, watchOS 8
From what I see on my devices, those sounds will only be played on the active device, in case your mute button on your iPhone is enabled or the iPhone in standby.
Also make sure, Do Not Disturb or a Focus mode is not enabled
Use Focus on your iPhone or iPad - Apple Support
Did you already force restart your devices?