Cannot change Workspace Capacity Tier

Hello mora11 

Other users have reported similar issue in this forum 

https://community.fabric.microsoft.com/t5/Fabric-platform/Purchased-capacity-not-showing-in-workspaces/m-p/4357408

here are some possible solutions :

If the capacity was recently upgraded, wait for at least 24 hours to see if the issue resolves itself

or 

Try reassigning the Fabric capacity to the workspace. This can sometimes trigger an update in the displayed capacity

If the issue persists, it’s advisable to raise a support ticket with Microsoft for further investigation

please accept this solution if this is helpful