how do I unpause iCloud photos uploading? stuck on pause/updating/conserving battery power etc.

How do I start uploading to iCloud photos? I have an iPhone 8 Plus running iOS15.6.1.

I have about 8000 photos and have purchased sufficient space on iCloud storage.

the phone keeps pausing the upload. it sometimes says it is conserving battery power (it is plugged in.

other times it is "updating" but nothing seems to happen.

I've been trying for 2 days so far. I've restarted the phone. I've turned icloud photos on and off. please let me know if this is fixable, or if something like google photos works better for my phone.

thank you

• Jon