Looks like dust on the sensor to me, also because your circles are approx. in the same place in your examples. In order to make sure, take a shot of a bright featureless light with aperture closed as much as possible. Then, process the image with high contrast settings. Changing the haze, clarity and structure sliders can help too.
Using NLP revealed something on the sensor of my camera that had not shown in ordinary shots:
Note: The obvious fibres were on the negative, the less visible “elbow”-shaped item was on the sensor.