Running digikam 5.1.0.

When I am importing pictures from another folder on the disk, I want to rename the files based on the date and time at which the picture was taken and put them in the albums based on this date.

When I select these options, digikam renames the pictures based on file modification date and creates albums based on the same.

How do I get the desired behaviour?

Not a Digikam expert, but I'd recommend you that in case what you wan't isn't possible, you file a bug requesting that feature to bugs.kde.org since developers don't seem to read these forums too often.