Slide master layers

It's been two years since the last post on this thread, so here I go. I am trying to streamline the creation of our content. I have Slide Masters formatted and prepared for each slide type we need in Storyline. However, I still have to manually add three slide layers to each slide type in the project. This slows down the process significantly if anyone other than me is creating content.

Has anyone figured out a way to add functional slide layers to a slide master, so they are available when you select that slide layout? Keeping my fingers crossed that in 9 years, someone has figured out some workaround.

Thanks,