I just took a new picture, it appears at the top of the gallery. My camera settings are configured to store pics directly on SD card, I also have around 2.8k pics, from previous years and devices, in other folders, they still appear on a chronological order in gallery.

Actually, earlier today I did reset the media database, and rebooted the device (I did reboot because after the db reset the gallery had 0 pics, so I did the reboot after 10min or so, there might be an issue actually there).