Android downloaded images not in gallery/fotos

When I download images via Android client, they are not shown in the Gallery App or Google Fotos App. I can find them with an explorer app in the selected download folder (/storage/emulated/0/Android/media/…).

After some time (and hour or more) they show up in the gallery app. I’ve read that there is a process on android scanning folders for new media files but it should actually run more often so it should not take that long until images show up. I’ve experienced the issue on 3 phones already (2 different Nokia and a OnePlus).

Is there a way to fix that?