Yes please!

It would be great to edit custom templates.

I have a diffliculty to remember what settings I have made in a custom template or to alter minor settings

Currently you can clone and edit all you like, but this is great feedback, and we should be adding the ability to edit templates as well :)

Since there is an option for customising the templates, why not make it possible to set your favourite one as "default"?

I like this but I also want to be able to use a YouTube video and cut it into shorts on Desktop