FP3+ running /e/OS 1.6-S (Android 12), providers: WEtell (SIM1) and ALDItalk (SIM2)
Got the cell broadcast message at 11 am sharp. NINA as well (of course only once I activated internet connectivity 
). Last but not least: Sirens! (fortunately we have them here for many years uninterrupted)
Other than the sirens, no sounds either, but my phone was on vibration only. Interesting to see what cell broadcast can do on our phones without explicit authorization (keep screen alit, but not audio alerts?).
I’ll submit my experience at
www.warntag-umfrage.de
(this link should be shown in NINA, too).
P.S.: I’ve allowed myself to merge the two topics.