IPv6Freely

Okay so looks like if I go to Layer > Expand Stroke, then select both of the two curves that are now created from the two strokes, and use the Subtract button, I get the result I want. Which... is basically exactly what the video was about in the first post of the thread. So... still not what I'm looking for. I guess I could always fake it by just doing a 10pt white stroke on top of a 13pt black stroke, but that still means it's missing the functionality I'm actually looking for. I'm on my last day of my Affinity Designer trial, so I guess until that functionality is introduced without having to do these workarounds I'll be sticking with AI.

Okay, so I did that. I have a 13pt stroke in black with a 10pt stroke in red. Now, how do I remove the red so that all that is left is a 3pt black stroke that is 10pt outside the blue box? I don't want multiple strokes on a curve, I want the equivalent of an offset path in AI.

I have no idea what Appearance Studio is. So maybe that's why.

Googled "offset path affinity designer" and came across this. This is seriously the only way to do an offset path in AD? I'm a designer of bags and backpacks and I use that tool more than just about any other in AI for quickly adding seam allowances to my patterns. I found out about AD today and downloaded the trial. I guess for now I'm going to have to keep paying the ridiculous Adobe tax...