Creating a photo grid/collage from Photos

I want to create a simple photo collage in the form of a 2x2 or 3x3 or 4x4 (etc) grid.

Using Siri Shortcuts on iOS12, this is super easy. There’s both a combine images function (that supports auto grid with auto spacing) that simply combines the photos in their original aspects and a Photo Grid shortcut in the gallery that automatically crops the photos to be square then combines them.

On the Mac (Mojave), however, it’s not that easy. I assumed there'd be an easy way to do this as an export from Photos. Why use the Mac? Well, when I want to combine photos from my Canon 7D that sync to my iPhone by iCloud, it’s extremely slow to load them to on phone. That’s why. Sometimes it just fails. I can open the individual images and view them, but downloading full RAW version (as this action forces) doesn’t always work. Probably due to a slower internet connection than Apple believes exist.

Automater doesn’t have the same functions as Siri Shortcuts.

Photoshop is overkill, and expensive.

I know there are multiple apps on the Mac App Store that do this - it seems none are great, they all try to add extra features beyond the basic functionality I want that make them annoying. Pages and Keynote can do it but it’s clunky and you’re forced in to an A4 or standard size sheet. Word & PowerPoint are clunky, too.

Is there no easy, built in way to do this from Photos in Mojave (or through some other built in Mac feature) like there is on iOS12?