Xdg isnt just config. Using .config (xdg config) on Mac is super weird.
Xdg is also, .cache (xdg cache dir) for data that can be cleared on reboot allowing you to use tempfs for it (of course you can't because a bunch of shit uses it as a persistent cache for things they should be putting in .local/share/. (Xdg data dir).
This whole mess is so utterly fucked I gave up caring and just let the mess be.