Like sure, someone particularly interested in your home nextcloud instance could probably find their way in eventually.
But if you are concerned more about dropbox killing your account due to nonpayment, cloud backups getting encrypted and the master key being lost, cloud engineers snooping on your files, cloud platforms targeting ads based on your downloaded files etc etc etc it offers an alternative.
Like sure, someone particularly interested in your home nextcloud instance could probably find their way in eventually.
But if you are concerned more about dropbox killing your account due to nonpayment, cloud backups getting encrypted and the master key being lost, cloud engineers snooping on your files, cloud platforms targeting ads based on your downloaded files etc etc etc it offers an alternative.