Can you provide any more specific details about the phone and the issues? Seems you have Verizon. Do you have a Samsung account, a Google account or both and more. Is sync enabled? Do issues still continue with airplane mode. I am trying to figure out if an app could be responsible or someone with access to the account and syncing settings.
Factory reset and do not restore your backup and change your passwords.
Galaxy S21 Ultra 512g(VZW), Galaxy Book (original, VZW), Tab S4, Galaxy Watch3 (VZW)