No notifications on new phone despite all being switched on

Since changing phones from Samsung S21 - S24 I no longer receive notifications from the app. Notifications are switched on in the app and have permissions on my phone settings. Old app on old phone was uninstalled.

Was it a transfer from the old phone to the new?

There is a suggestion that this process can mess up some of the Monzo settings, so Iā€™d suggest you delete the app, restart the phone, then re-install the app (and login), and see if that fixes it (it seems to be the remedy for the majority of odd behaviour with the app).