Hi cdibbs,
It looks like the Snapmaker controller is pretty much your basic vanilla Mach3 style G-code setup. I'd suggest trying the Mach3 or the GRBL post processors for milling stuff. Try a dry-run with the tool zeroed out above your actual cutting area and see if it looks like it's traversing toolpaths the way they should be. The Easel post is non-modal for coordinates, where it includes a value for X Y and Z with every command block, which some controllers prefer, so it might be worth testing that one out too if the Mach3/GRBL posts don't work out.
Make a small canvas with a thin Z size and then create a basic tool definition and then from the 3D Contouring operations category create a Parallel Carving operation. Generate a toolpath that cuts to the bottom of the canvas, and has a big cut stepover, and export G-code for that.
Here's a test project you can use to export G-code for to see what works for your controller: https://cdn.shopify.com/s/files/1/0308/9658/6890/files/3x3_Test_Project.pnc?v=17...
If the Mach3, GRBL, and Easel posts don't work properly you can reply to this thread or send us an email at support@deftware.org :]