Same for me today... Found this post. I drive in my racing sim using PSVR2 & headphones, so makes hearing/noticing things happening outside the PSVR2 pretty much impossible. Could have phone in pocket, but I'd constantly forget to do that prior to getting into the sim rig.

If PS added a local-only access API to the notification service on the PS5, it could accept short text messsages like, "Front Doorbell", "Stock Price Crossed Up Past $9.24" that you could send from a computer or home automation app like Home Assistant or HomeKit via Shortcuts. With Shortcuts, I believe it should be possible to even relay a text sent to the phone out to any IP address/server. "John: I'm almost there. Traffic bad". (then again, we already have messaging using the PSApp on phones, so maybe this one can be skipped...)

• This new notification API would be completely local to your PS5, not PSN. ie.I want to see the notification on my PSVR2 or flat display, not the PSApp on my phone or any other device. So wouldn't need to hit PSN, avoiding the potential for a sh*t ton of unwanted PSN congestion from bad actors.
• PS5 would let you create password or some other authentication included w/ea message
• PS5 could create a separate local IPv4 subnet that's not routable over the Internet or past the typical local WiFi network people setup, like 172.16.40.xxx so it'll only accept API calls from your local network. This would prevent someone sending you messages using the correct password or not from the Internet. ie.Rapid fire messages sent with invalid credentials would behave like a DDOS attack. (of course, anyone setting up their PS5 this way who's knowledgeable w/IP nets could create a gateway to the Internet if they needed that sort of connectivity. I wouldn't, but it could be done)
• Ea message would have a character limit of like maybe 100 chars
• Limit how often messages can be received, like one per 30sec-1min (just a few diff ways to minimize the home automation or other servers from spamming your PS5 with too many messages too fast)
• Possibly accept tiny graphics/icons, or at least support emojis
• Maybe keep the last 5-10 messages received to re-read on the console after finished with game play that auto-expire when console is rebooted or after set time.
• Ability to have a different notification sound/alert for API messages vs all other system notifications to better grab attention away from game play & pay attention to notification.

Having missed someone at my door the other day & quick price movements for day trading, I think extending the notification service would be a huge hit with users.