If you and your partner both have iphones then iCloud should be sufficient for keeping the photos to yourselves if you turn on Advanced Data Protection. I think it requires you and your partner to have two yubikeys at a minimum though.
https://support.apple.com/guide/security/advanced-data-protection-for-icloud-sec973254c5f
Photos encrypted at rest, only you and your partner will have access to the keys. If you want the convenience of icloud backup then the government would be able to subpoena your decryption keys from your phone backups, but it’s not going to be available for casual employee access. Automated tagging/face matching is done by your iPhone when it’s plugged in so there’s some organization. Nothing close to Google’s AI organization.
I know Apple is a shit company. But they’ve learned a thing or two after the Fappening.
Advanced Data Protection should be the minimum setting for you to consider Apple as your photo storage. Your photos will auto upload from your phones, apple has partner sharing so photo libraries will automatically be shared between you and your partner, and they recently implemented a system similar to “signal key verification”, but again limited to ADP turned on.
Otherwise you’re looking at Proton or Tresorit.
What is this photo storage thing? All I can find is proton drive.