It's actually kind of the opposite with DB [1]: Regional trains are decently on-time, and commuter trains even more so because they usually have dedicated tracks. Long-distance trains and cargo trains are the ones with abysmal punctuality, the former because the schedules are so tight that a random passenger coughing at the wrong time can fuck everything up, and the latter because they have to yield when a late passenger train has to make up time.

[1] Source (2024): https://zbir.deutschebahn.com/2024/en/interim-group-manageme...