Hi A_N, thanks for sharing the details and screenshots. This issue usually happens when Windows cannot fully verify your Microsoft account for ESU enrollment, even though the account looks correct online. Here are a few things you can try:
First, remove and re-add your Microsoft account on the device. Before doing this, make sure your PC is not joined to an organization or domain and that you have a backup of your important data. Then go to Settings > Accounts > Email & accounts, select your Microsoft account, and remove it. Restart your PC, then add the account back and sign in again.
Second, check that your device is set as a trusted device. Go to https://account.microsoft.com/devices, sign in, and confirm your PC is listed. If not, add it and mark it as trusted.
Third, verify that two-step verification is not blocking the sign-in process. Temporarily disable it or use an app password to sign in if prompted.
Last, if the issue persists, create another local profile with administrator access, sign in with your Microsoft account there, and try the ESU enrollment again. You can also run the Microsoft Account Troubleshooter and check for any pending Windows updates.
If you found the response helpful feel free to mark my answer as helpful/accepted, it might make it easier for others to find the solution too.
Best,
Carl