The patch just hit Xbox about 30 minutes ago. I still can not subscribe to any content. It still shows the basket and tells me Im missing the required content. It does not recognise a single DLC i have installed out of 42 DLCs. I did logout and back in from Dovetail Live Service to see if it fixes it.. Nope. Obviously i did not try to uninstall 42 DLCs and re download 190 GB agin yet to see if that fixes the problem. This was supposed to be working again after the patch we just received on Xbox. Xbox Series X
The reason for this could be that the Core Game hasn't been updated yet. So far I've only gotten updates for Linke Rheinstrecke, Bremen-Oldenburg, Voralberg and Dresden-Riesa
You can get around the Creators Club "bug" by subscribing through the website, it seems that doesn't check your content and will then appear for you to select in game. https://creatorsclub.dovetailgames.com/