Push Notifications exploding

About a year ago, My iPhone 13 suddenly began using tons of data, all of it going to "push notifications." It drains my battery, too. I have eliminated my watch, bought a new phone (same model) turned off all notifications, removed every app I don't use all the time, and the only thing that works is to turn off the data. At this point I rely on wifi for everything. Example: yesterday, I turned the data back on for 3 hours, sitting in my house. I was supposed to be connected to my home wifi, but in that 2 hours I used 360 MB of data.... 359 of it on push notifications.

I saw that this question was posed a couple of years ago, but never saw a resolution. HELP????

I have been to the Apple Genius Bar five times for this... we've reset the whole phone three times. Nothing helps.