y2kbug the mail server could still be accessed
Yes the same with Microsofts Office 365 used by hundreds of millions of users, they are not afraid to leave their ports open, and its Microsoft 😉
Moral of the story: Use safe passwords. Use 2FA. And use App passwords for accounts on devices.
y2kbug fail the IP with incorrect login, immediately for years.
That is a bit overdone I would say and could potentially lock you out, if your IP ever changes.
If you use generated passwords as mailcow already suggests them, noone can break your passwords even if you set the ban to 1 minute.