I use this to sync my wife's photos to Immich and it works great, however the auth process is a bit of a pain (not the fault of icloudpd) and have to reauth every few months.

It is a pain.

I’ve wrapped it in some short scripts which notifies on auth failure and it’s an easy process to run the auth script. But there’s no way to avoid the bi-monthly inconvenience I don’t think.