Microsoft Intune - Software installation

I am a beginner using Intune to manage PCs (Windows 11) and Android devices.

When adding a new PC with Windows 11, the following happens: The user logs into the computer with their email account from our company administration and starts Windows 11 (Business) and complete the Device Registration in the "Unternehmensportal". The user (who is supposed to be a standard user) is set up with an "Administrator" profile. If I change the user to a standard user (logging in with the company's admin account on the same computer), I can no longer install any software and get the message "Installation is blocked" (or something similar) when running the installer. There's no prompt for admin rights or an option to run the installation file as an admin. On another user's computer, everything works without problems. No policies are configured, at least not to prevent software installations. The user should not be able to install software independently, and standard users should be standard users when first logging into a new device.

Who can help me?