Hey Jim,
thank you very much for your response!
I checked the Audio-MIDI-Setup but there is only one setting that I can change there, which is the sample rate. Currently it is set to 48 kHz, so I tried lower and higher alternatives. Unfortunately, it didn't change the problem.
As for my system, these are the specs:
3,2 GHz 8-Core Intel Xeon W
32 GB 2666 MHz DDR4
Radeon Pro Vega 64 16 GB
macOS Big Sur (11.1)
Best regards
Boland