Manual "auto-upload" for Nextcloud app

I would like to upload the existing pictures that I have on my iPhone (on iCloud).
I tried going through the app auto-upload feature but it is painfully slow, much slower than the normal PC upload (I opened a GitHub issue for Android here https://github.com/nextcloud/android/issues/6794).

There are about 20000 photos, so going this route is not really feasible unless they fix the problem, which I find unlikely given that I can find many other open issues and forum posts about this exact same thing dating back a few years.

I would like then to get the pictures out of the phone and upload them manually, in the same way as the subfolder option does in the app. Moreover it would be great if the Nextcloud app on the phone would recognise these photos as uploaded and do not try to upload them again.

So at the end of the day the app would behave as if the pictures had been uploaded correctly by itself, and continue uploading new pictures as they get taken.

P.S. I also have an Android and there I managed to get all the pictures (different from the ones on iOS) uploaded. What happens if I reinstall the app or change phone? Does it recognise that the photos have been uploaded previously and not attempt to upload them again?

It does not recognize those and it will try to upload them again just like you said. It is very bad behaviour and bad design. There absolutely should be some function to recognize the files allready on the server and possibility to choose “There is allready file named as … would you like to replace it or keep the old one. Do this action also to the other million files that you have.” There actually is the function to choose which one to keep, but it will ask it for every file and you can acces on it only fronm your androids active notifications and it will go on and on. And it will be very difficult to cach all the notifications and it is still uploading for many many gigabytes worth of files. This really should be fixed.