Vipar,
So, I have been working on your project and testing out a few ideas. I noticed that your GameInstance was created in code instead of blueprints, which is fine. However, when I started to look over the GameInstance, I noticed that there wasn’t any code added in for achievements.
Please look over this [documentation][1] again and make sure that you’re updating the correct blueprints or code in game. If you need a more visual guide, open up Unreal Match 3 and go to Edit > Project Settings > Maps and Modes and click on the eyeglass that’s beside “Global Game Instance”.
Let me know how it goes!
Using Google Play Achievements in Unreal Engine Projects | Unreal Engine 5.1 Documentation