You can make standalone Garmin Wifi Apps for free (you only have to pay if you want to charge).

Do note that it's very janky. By default web requests proxy via the phone - if you want to try wifi you have to switch into a "modal wifi mode" - do a batch of web requests and logic - then switch back into "normal" mode and then do something with the saved data.

You cannot push notifications from wifi but you could do:

1. request to open the app using a background service

2. toggle wifi mode

3. fetch the data and close the app

4. create watch notifications from the background service.

You may need to acknowledge the request to open the app with a button press - but I've also see examples of it just opening (not sure of conditions though).

If your Garmin is already paired with a wifi AP turn off your phone and give https://apps.garmin.com/apps/78a3fa7c-6f78-4d0e-94cd-b9bd874... a go to see the UX (needs Gemini API key).