You can remove the 'iCloud' notification by starting the setup for it, and then cancelling.
It's a dark pattern Apple repeats with a lot of notifications - they are not dismissible and give the appearance they are only resolvable by completing the notified request, but it actuality just starting the setup and then cancelling will resolve it.
Honestly that sounds more like a dark pattern (advertising "notifications" you can't dismiss) + what they would consider a bug (dismissing the adware on installation start instead of finish).
It's a dark pattern Apple repeats with a lot of notifications - they are not dismissible and give the appearance they are only resolvable by completing the notified request, but it actuality just starting the setup and then cancelling will resolve it.