@Kirk: I have uploaded the file. Everything else (except the preview-window settings) works fine.
@Soizic: I am using the base PM-version (not the plus one). I have the basic Macbook Pro M1 with 8 GB RAM and 256 GB Storage. I work with 30 GB nef-Files from a Nikon Z6. At the moment there is no problem, but you feel that the GPU is not a powerful one. But if you want to know some benchmarks from Capture One:
I have a test-catalog with 593 nef-files edited in color and black-white and different settings applied (corrections as well) and exported it to jpg 70 quality and 4000 px for the longer side of the picture:
.) MBP M1: 12:17 minutes
.) HP 830 G5 (Intel i5 8350U, 16 GB RAM, 1 TB SSD-storage): 35:00 minutes
.) Workstation (AMD Ryzen 3900X, 32 GB overclocked RAM, 1 TB SSD-storage, untervolted and slightly overclocked Radeon VII): 3:18 minutes
During exporting the MBP didn't make a sound, completely silent. Capture One uses for export CPU & GPU power (which Lightroom doesn't).