Hello Aron Depaz, thanks for posting this in our community.
Sorry to hear you're experiencing this issue, especially after already purchasing a valid Windows 11 Pro license. I understand how frustrating it can be to run into activation problems after replacing your motherboard, especially when everything was working fine before.
To begin, you may want to check your license type. Open Command Prompt as Administrator and run the command slmgr /dli If it shows "Retail," your license is transferable to new hardware. If it shows "OEM," the license is tied to the original motherboard and cannot be transferred.
If your license is transferable, try using the Activation Troubleshooter. Go to Settings, then System, then Activation. Click on Troubleshoot and select the option that says “I changed hardware on this device recently.” Sign in with your Microsoft account, choose your current device from the list, and click Activate.
For more detailed steps, you can refer to this guide: Reactivación de Windows después de un cambio de hardware
Kind regards,
John Oli