Anyone have experience debugging post processors?

I'm using VSCode and the F360 Post Processor Utility extension, trying to follow NYC CNC's tuts about it (https://www.nyccnc.com/vs-code-editing-posts/ and https://www.nyccnc.com/beginners-guide-editing-post-processors-fusion-360/ and a few other search results).

I'm on an M1 MacBook (hoping this is irrelevant, but I'm suspicious).

I'm fairly comfortable in Code, as I've used it for several Arduino projects in the past (platformIO), but something here is eluding me.

I've downloaded the CNC Exporting Post Processor ("export cnc file to vs code.cps")from VSC. When I attempt to post from Fusion using that processor, Fusion gives me a "success" notification at the bottom right corner, then Code opens up a file with the title of my program, but everything is completely blank - no "fail" message, and no "success; your file is located [here]" message or anything, just a blank file.

I can open the extension's "built-in" CNC files in the "CNC Selector" section to debug just fine, but I can't bring in my own files. The "custom" category appears, but there is nothing in the dropdown. Even stranger, I think; when I right-click to manually import a CNC file, in the Finder browser that pops up, all my .nc files are greyed-out and not selectable.

I've found a few mentions of modifying the "post executable" (filepath) in the vscode extension settings. All these mentions are in the context of Windows, and I cannot for the life of me figure out how/if this applies on macOS (13.0 Ventura, FWIW).

I'm happy to humor anyone's suggestions for troubleshooting/resetting/posting screenshots/whatever.

Thanks in advance!