Yep. Had that happen with the United app a few weeks ago. Unsolicited spam sent via push notification to my phone. Turns out that they added a bunch of notification settings - of course all default to on.
Turned them all off except for trip updates that day.
Best part is- yesterday I received yet another unsolicited spam push message. With all the settings turned off.
So these companies will effective require you to use their app to use their service, then refuse to respect their own settings for privacy.
Sending ad notifications is a recent trend, normally Apple guidelines don’t allow it, but they know that Apple cannot much fuss about with all the regulatory pressure.
It’s the enshitification of the notification system, the apps are already filled with ads and now they’re making you open the app or splash things on your face.
Why do you even need the United app? They have a website.
I've taken to "Archiving" apps like this on my Android phone. When I need it, I can un-archive it to use it. Keeps the list of things trying to get my attention a little bit smaller.