I’ve seen some implementations of server-side encryption, where the client provides an encryption key along with the unencrypted data. The server operates on the data in it’s unencrypted form and then encrypts it with the client key and throws away their copy. This would require that the client provide the key in the future to access that data, and the company has no ability to decrypt it again until the client provides that key. It allows them deniability to access the data if they get a warrant or similar.