Webcam Autofocus does not work when resolution is set in python opencv

Question

I was using opencv to open a camera stream and to take photos with it (Windows PC). The Webcam (NexiGo N660P 60FPS 1080P) can record videos with 1920x1080 pixels. So the code i used worked an i was getting sharp images:

cam = cv2.VideoCapture(0)
cam.set(cv2.CAP_PROP_FRAME_WIDTH, 1920) 
cam.set(cv2.CAP_PROP_FRAME_HEIGHT, 1080) 
cv2.namedWindow("Bild")
    
global img_counter
img_counter = 0

while True:
    ret, frame = cam.read()
    if not ret:
        print("Fehler")
        break
    cv2.imshow("Bild", frame)

    k = cv2.waitKey(1)
    if k%256 == 27:
        print("Kamerastream geschlossen")
        break
    elif k%256 == 32:
        img_name = "Foto_{}.png".format(img_counter)
        cv2.imwrite(img_name, frame)
        print("{} gespeichert".format(img_name))
        img_counter += 1

cam.release()

cv2.destroyWindow("Bild")

I have not changed anything and since a week now the camera does not focus anymore (Edit: it no longer focuses on the right level. So the autofocus still works, but not as before), when i run this code with python. When im running the code without setting the resolution, the autofocus works normally and i get sharp images again. When i record a video stream with the standard camera app on my pc, the autofocus works normally too, even at 1920x1080 pixels, just as it did before in the program.

Since I have not changed anything and have not made any updates, I wonder why it no longer works. I would be very happy for help :)

->I made a few restarts and also tried the code away from the original program (GUI application), but the result remained the same.