Hello Hawk132,
Can you recognize where these notifications are coming from (what app)? If you recognize the app, you can disable the notifications and/or deem if they're legit.
If they're coming from an email, I would probably ignore it especially if you don't recognize the sender. Never click on links or attachments from unknown senders. You should interact with Cash App through their app or their legitimate website, not by other methods.
If you received a link (as the title states), DON'T CLICK IT! Navigate to the official Cash App website by yourself. Again do not interact with unknown senders.
If you believe you were hacked, you should change your Apple ID password and device passcodes. I would also recommend going through Safety Check (within Privacy & Security in Settings) and reviewing what people and apps have access to your data and revoking as needed. Step 3 of Safety Check is the most important. It will show any devices currently logged into your Apple ID. If you do not recognize a device remove it immediately!
I hope this helps!