Uploading photos to iCloud

I know that. I know also that you have to change auto lock to “never”. I know that the upload is really clunky and irritating if you try to do it on mobile data (which in this day and age is probably what a lot of people want to do) and it is also very irritating if you try to do it on battery power. Because it keeps bossily trying to save battery power - unasked for!!! All that is known. However even on WiFi and plugged it it won’t work well and having managed to achieve 5% upload today, I’ve just rebooted my phone and now it says only 1% is uploaded!!! It’s a problem. Can you help?

I’ve got 2TB storage on iCloud and about 50GB storage left on my iPhone 11Pro 256GB handset. I’ve hardly used the 2TB storage partly because it seems so difficult to get to upload anything into it! I want to upload my photos as I am worried that I will run out of storage on the handset. But for one month now it’s been impossible. I have updated to iOS 14