I have a problem, the calendar application icons are not visible after the eos installation. It does not even appear over time. I have reinstalled the system several times and in vain, it doesn't work. And there is no icon only in this menu, in the rest of the menu it is
Go to the AppCenter and install AppEditor https://appcenter.elementary.io/com.github.donadigo.appeditor
You can configure the App Icons for each app. So just select the calendar icon for the Calendar app.
Idk why you face such problems though, maybe it's releated to the language you use.
It looks like this is an issue in Calendar. I've filed an issue on GitHub; you can give that a 👍️ reaction to show you're affected, and you can use the Subscribe feature on GitHub to get a notification when there's an update.