@MaRceL A a Thanks for posting in our Q&A.
For this issue, not all users have the permission to access intune portal. Generally, a Global Administrator or Intune Administrator account can access all pages in intune.
To clarify this issue, what did you mean "activate a device linked to my university Microsoft account"? Did you mean that you want to enroll your device to intune? If yes, when your user account has an intune license, you can enroll your windows device via Settings > Accounts > Access work or school > Connect > Join this device to Azure Active Directory > enter your user account and password.
If there is anything update, feel free to let us know.
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