Photodownloader: "connecting to device please wait"

There is no problem connecting  Nikon D500 and load the photos to my laptop with Photodownloader or LR-Import. (newest and older Versions)

There is a problem connecting D500 to my PC since two months.

If there is one RAW-photo on my memory card Photodownloader needs 10 seconds "connecting to the device"

If there are 10 photos on the memory card  Photodownloader  needs 100 seconds "connecting to the device".

After that time the photos are loaded quickly.

Photodownloader seems to be more clever than Lightroom CC Classic.

In the mentioned  cases above Lightroom-Import tells me after 10 resp. 100 seconds : " no photos found".

Any ideas? Thank you!  And please: no proposal: "Take the cardreader"