I purchased Cyberpunk on Galaxy it shows there as owned 6 mo ago. Plays fine. So I ordered the DLC Phantom Liberty on Galaxy and it shows its paid for, but doesn't show in the owned games and cant install it.
They claimed i was using an old version of Galaxy so I downloaded new version, still no joy.

WHAT amazes me is someone stated it would be better to buy it on GOG and not Galaxy (like they aren't the same?).
So when I went to GOG it shows I dont own Cyberpunk, whats that all about?

On Galaxy Phantom liberty stated it was paid and 'in your library" but the library didn't show it as owned. WTF?

My solution to this problem is to delete folder 'storage' in location: "C:\ProgramData\GOG.com\Galaxy". Next GOG Galaxy run all purchases and updates will show up.

I searched on every forum on internet and eventually end up fixing this by checking whether you are using the correct account.
https://thegeekpage.com/microsoft-store-is-not-showing-purchased-games-and-apps/