Google Sheets - COUNTIFS with timestamp

I have a column in a table that contains the date and time. This is the form

15.06.2020 09:43:2417.06.2020 08:21:0418.06.2020 12:11:34

or also

2021-01-21 11:57:342021-01-21 11:58:022021-01-21 11:58:26

Now I am trying to count specific time periods via COUNTIFS, which unfortunately I am not able to do.

It does not matter if I use

=COUNTIFS(ticket_data_and_metrics!C:C;">15:00:00")

or

=COUNTIFS(ticket_data_and_metrics!C:C;CHAIN(">";TIME(15;0;0))

take, it does not produce a result that is correct (either all entries are listed or only 1 or 0.

Any idea how I can solve this with COUNTIFS without splitting the timestamps into two columns since this is a report that updates automatically.