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.
What brand are you using? Never had this issue with Pixels or Samsungs.