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.
Edit: I’ve disabled DOZE according to https://stackoverflow.com/questions/40204605/android-completely-disabling-deviceidle-doze-in-android-m Hopefully that helps.
FWIW, this is not normal or expected, most users get their notifications more or less instantaneously. Maybe knowing this might help you search for information about whatever it may be that prevents this from working for you.