Issue with calendar notifications and change of primary e-mail

Recently, I changed the email address of my Apple account from an @outlook.com domain to a former @iCloud.com alias email. The whole process went smoothly, and the @iCloud email is now listed as the primary email at https://account.apple.com/account/.

However, I'm not receiving notifications in the Calendar app. Notifications are set up properly on iCloud.com for the primary @iCloud.com email. Siri only suggests new events in the Mail app.

I’ve read that this issue might be caused by using an iCloud.com alias, which doesn’t support notifications, but in my case, the @iCloud.com address is already set as the primary email. So to me, this seems like an iCloud configuration issue rather than a user settings problem. What should I do?