I don’t trust Apple for this exact reason.

For those interested in the silver bullet to backup iCloud.

Get a Mac mini with enough space for your photo library and wire it into your network. Sign into iCloud.

For photos open the app and change the settings to store full res photos locally.

Enable iCloud desktop and documents sync.

Two options

1 - Sign up for Backblaze and ensure you map the folders from iCloud and photos that are being synced to the device. Let it run and do a full sync. I use this option.

2 - Buy an external drive with a lot of space and use Carbon Copy Cloner to mirror your drive. The caveat is your at the mercy of a local copy that a home fire or electrical incident can destroy.

I like Backblaze for the sheer constant syncing it does and they allow me to set up an encryption key so they don’t have access to my data.

I do that, and I'm also planning to use icloud photos downloader [0], a python script to download photos, so I can download those directly on another machine running Linux.

[0] https://github.com/icloud-photos-downloader/icloud_photos_do...