A couple of ideas come to mind, first welcome to the group and I do hope you learn loads more in due course. Ask questions if un sure that is what the group is here for, many are very helpful and knowledgeable.
Like anything what work you put in will relate to your exported efforts.
1: If you have not looked at "StoryBlocks" ? please do it is very part of LumaFusion, here you can use the audio and background videos to make some templates.
2: If your wishing to have a self made template I often do this and will one day get around to selling them, how much would you pay ?
Here is not the place to sell my wares of course.
I would however be interested in what you would be looking for exactly to help me build the types of designs people may wish to purchase.
(Apologies in advance if I have over stepped the mark LF ?)