I was on Dribbble and saw this shot. They made this seemingly normal-looking border-radius yet it looks different. How would you achieve this in Figma or AdobeXD? Shot link
I don't think this is a normal corner radius. Looks like the corners have been manually edited. I think that's what you are noticing here and describing as cosy - a hand made look which is naturally less regular.
You could start off with a regular radius, then edit the Bézier curves manually
Sorry, I'm not a Figma user. This example is in XD but I don't see any reason this couldn't also be done in Figma.
Copy and paste duplicates of the other three corners, and flip them accordingly, then use the Add (aka Union/Unite) boolean operation to make one shape.