Date format of the form submission date with merge tags

I need to display the form submission date in the format DD.MM.YYYY or DD. Month YYYY.

The only available submission date merge tags are {date_dmy} and {date_mdy}.
Both show the slash “/” as separator, but I need the dot “.” for the central european date format.

This is not about date input fields, but the submission date merge tags.
How do I get it to display the way I need it?

Try the {date_created} merge tag instead, it supports custom formats. See the following page of the documentation:

Excellent! Thank you very much. Works great.