Counting different values in an additional process field

Good day! In our box https://goncharenkocentr.1b.app/ there is a need to make a report that will display all the different values of a certain additional process field along with the number of repetitions of these values for each person responsible for the process. In more detail: there is a list of centers, there is a list of course types, and a field "Course start date". It is necessary that for each center and for each course type the start dates are shown, and how many courses started on that date. Please advise which of the report templates might be suitable for this, and how, in general terms, this can be implemented. Thank you in advance.