As others have said, DB’s reliability (especially long distance services) can leave a lot to be desired.
That said, an impromptu “tour” yesterday to use the last day of a 10 day Inter Rail demonstrated that when it works, it can be quite impressive!
06:38 Berlin-Munich (to Erfurt) was 10 late leaving, but some spirited running saw that reduced to 6 mins. Train 2 to Bamberg was on time.
Third train (An RE service) was on time. Train 4 was an IC Nuremberg-Stuttgart which despite a 10 min late departure, was only 1 late at Stuttgart.
Next was the Graz-Frankfurt, 10 late from Stuttgart but only 4 late into Frankfurt.
Lastly, the 16:02 Frankfurt to Berlin which left about 5 late, but notwithstanding an at times, leisurely pace (must have a padded schedule), saw an early arrival at Berlin Hbf at 19:59!