Photos in random order

I use nextcloud to transfer photos from android to Ipad.
Automatic transfer from Android (samsung) to NC works fine but the pictures in nextcloud are displayed in a ‘random’ order despite the fact that the file names of the photo is built from date and the time. Unfortunately, the transfer to IPad preserves this wrong order and I need to spend a lot of time to sort them in the iPad.
Has somebody an explanation for that?
Did I made something wrong in the parametrisation of the automatic transfer in the android app?
Thanks in advance.
With my best regards