Ios app changes file date during photo upload

I originally chose nextcloud to get my photos without losing the file date information. The ios app stored my photos on the nextcloud space and I could download them and the photos still had the original file date. This is helpful as I like to see my photos in the order of the creation.

It seems that this process had changed during the last months. After the sync the file date on the server the file date is the upload/sync date. Videos are still not impacted of this change, but photos are. It happened when using the heic file format as well as when converting to jpg. What can I do to change this and keep the original file date?