Regarding portfolio

Do designs made from freepik is accepted for samsung portfolio submission as it is accepted and for other mobile themes, or is it necessary to make all scratch designs

You would not be approved if you submit anything but original artwork.

Read Tony Morelan’s Blog on How to become a Theme Designer for information on what the review team is looking for.

Ron
Samsung Developer Program

It’s unfortunate, because once accepted, so many sellers just resort to loading hundreds (if not thousands) of themes and wallpapers made from sites such as Freepik.