Sorry, I wasn't clear on the page, just in my head: I meant, can't you create some files in another program to open in Luminar and use as empty canvases? Say, small medium & large in 16x9 ratios for your Lumix images?

OTOH, I think this capacity (or lack thereof) helps show that Luminar is meant for editing one type of image, while Photoshop is clearly meant to do much more.