[2023] Missing DLC Tab in Launcher

That means MS/Xbox has not installed any DLCs, for some reason.

I did get this from one affected Gamepass user:

In case anyone else had issues when they purchased the season pass from gamepass.
The season pass shows no downloads and the dlc by itself looks like you need to purchase it.
Click the dlc and click the purchase.
It’ll change and say you own this already.
Click the same box that now says you own this already and it’ll ask you to download it.
Do the download and boom it finally adds
You need to do it for both northern and RC downloads.

Please let us know if that helps you!  

I don't know then. Can you test this on any other machine you might have access to?