With every version of Android it seems to be harder and harder to get real time notifications anywhere near real time.
Twitch notifications, Signal, WhatsApp, I often get these ten to thirty minutes too late.
I’ve excluded them from battery optimisation but that doesn’t seem to do anything. And I can’t find anything else.
I don’t care about battery usage. I’m always near a charger.
Android 13 on a Fairphone 3.
Apply the steps on https://dontkillmyapp.com/ to Google Play Services and Google Play Messaging, that may help. Also check if you have an app running in the background that eats all of your RAM and forces the OS to clear up scheduleable tasks.
Thirty minutes is way longer of a delay than I’ve ever seen. You may want to try a factory reset in case it’s a ROM issue. Fairphone has had its ups and downs over the years when it comes to the built in software.