I recently updated my Nokia G10 to the Android 13 and notifications are unreliable! I disabled all battery optimisations, changed apps to unrestricted. Make sure all notification settings for apps are on. Followed a bunch of guides but nothing worked.
After a few hours of not using an app I no longer get notifications for Signal, ProtonMail, Planta, and others. My partner has to send text messages!
I hate Apple and there cost but it looks like I have to get an iPhone.
@dean I went through this with my Pixel 2XL and on android 11. It seems to be an itermitant issue on android somehow? I really don't know, but that was part of what sent me to the apple side.