Today was another “warning day” for cell broadcasting (emergency notification) in Germany (regional only: “Rheinland-Pfalz, Hessen, Bayern, Nordrhein-Westfalen”).
Although I received the warning message including a sound in 2023, I only got a message (5 minutes late, though) today, but without any sound or vibration.
I have the same phone and, as in 2023, it is “muted” most of the time (no “DND”, but just no notification sounds or vibration turned on).
A friend of mine also has a Fairphone 4 and also got no warning sound today.
I also have a FP4 which runs the latest version of iodéOS. It was in my pocket (i.e. on standby) when it started an awful alarm noice (the message may have come from Hessen or Bayern). I was quite perplexed and fumbled around with it. I had just enough time to read part of the alarm message, before I permanently lost it and could not retrieve it. But to answer your question: yes, my FP4 definitely gave an acustic alarm. It seems that your “muting” may have succeeded in turning the alarm off. I have also turned off most acustic (or vibration) notifications of apps, except for the alarm clock, fossyfy calender, phone calls and magic earth.
Do you see entries under Settings / Notification / Wireless emergency alert / Emergency Alert History?
(In german Einstellungen / Benachrichtigungen / Notfallbenachrichtigungen an Mobilgeräte / Bisherige Notfallbenachrichtigungen)
Yes. I, for my turn, have enabled all Emergency alerts (“Notfallbenachrichtigungen”) - and my phone produced an acustic alarm during the national exercise.