U.S. v. Miller [1], which established the third-party doctrine, turned on whether "the business records of the banks" to which the defendant could "assert neither ownership nor possession" could be accessed by subpoena versus court-authorized warrant. (The context turns on bank records. Smith v. Maryland [2] expands it to "phone numbers [conveyed] to the telephone company.")
This seems trivially fixable with legislation. Requests made by the government to third parties in respect of specific persons' non-public (even if not strictly confidential) records require court approval or the first party's consent. Also, easier than trying to expand he definition of "houses, papers, and effects" [3] to cover our data in various clouds: defining, in statute, that there is a legitimate and reasonable expectation of privacy in the phone numbers one dials to speak to or message with another person or persons, e-mails one sends to a small group of people, handles one provides a messaging service marketed as encrypted, and articles (e.g. documents, photos and work products) uploaded to a third party's server for personal use.
[1] https://tile.loc.gov/storage-services/service/ll/usrep/usrep...
[2] https://tile.loc.gov/storage-services/service/ll/usrep/usrep...
[3] https://constitution.congress.gov/constitution/amendment-4/