Count puplished items and show a sequential number in admin list view

[jsr4id]

I have a table with "reports" that contains various fields. Some of the reports have the status "unpublished". I would like to assign the reports a year-dependent number, such as "08/2024".

The date (year) and the status should be checked in order to generate a sequential number. This number should be a pure display for the site and admin view and not a database entry. In mysql könnte das ein count(items) sein.

This is what the admin view should look like in simplified form:

How can I implement this? dynamicGet, customCode? I have no understanding of which method can be used to implement something like this in JCB. Oh and the picture shows the European date format DD.MM.YYYY.

[jsr4id]

Any Idea?