I'm not OP, but:

1. There's an app I use to operate and pay for the laundry machine in the basement of my apartment building.

2. There's an app I use during fire drills--I'm a a teacher--to confirm all my students made it out of the building.

3. There's an app I use to see the real-time location of the private bus which picks me up in the morning.

(None of these apps have equivalents on the web.)

The connecting thread is that I didn't really choose to use these services, someone else chose for me.

MobilePay (Danish payment system) is probably the main one I have left. The entire family is on either iMessage or Snapshot, but I could probably do with SMS or push a few of them to Signal, so not a huge lose there.

Everything else I have managed to move to my computer or replace with alternatives, but the payment one, it's basically the only way to transfer money to friends and family, that isn't a major hassle.

pagerduty/opsgenie is the one that got me