Unfortunately, We didn't work much with Child theme for Dokan. Theoretically and According to wordpress child theme method, the child theme should support all the functionality of Parent theme. So If you didn't do something wrong, the Child theme should've taken the override Template Settings.
As we didn't work much with it, we can't give you a correct idea about whats going on there. But we would like to take a look inside the hood. If possible, Provide your website Url and Administrator Login Credential and mark it as private. We will check it and let you know.