Hi donezio,
Apologies you are hitting this blocker.
I had seen something similar to this sporadically in development, but I have not been able to reproduce this on my end in recent times.
In the past, a combination of restarting Xcode, deleting DerivedData, and selecting Package Dependencies > Reset Package Caches worked to get me back on track.
Another thing to try is to select the Studio scheme to build the Studio package on its own.
Regardless of whether you can work around this, please file a Feedback request using the Feedback Assistant app. This will allow us to get to the underlying bug, or determine if it is already fixed in a newer release.
Keep us updated if you are able to get around this. Thanks!