If I was a betting man, I'd lay my money on mirrorless cameras being more susceptible to sensor dust ... The sensor is just there, waiting for whatever wants to jump / fall into the body when the lens is off. I struggled with an afternoon of cleaning spots yesterday in images from a Sony a7II. For whatever reason, Sony makes the shake process a manual action rather than auto when the camera is turned off or on, where I'd prefer auto for both.

I feared I'd have to get to a wet clean where I don't have full-sized wipes. I started with a sensor in this situation:



For the long pieces rather than circular spots, I could see these on the sensor with good light and a magnifying glass.

My first tool was a Giotto Rocket-Air and running the camera's sensor clean a few times.



The strips are gone. Maybe hair? I don't know what they are. The next tool is a Sensor Brush. It would seem this could add more than it removes. I blew the brush vigorously with the Rocket-Air, both to remove any dust in the brush as well as to build a static charge before touching the sensor.

Much improved, lots of spots gone, some new stuff arrived.



Another round of brushing and blowing and cleaning cycle and the final result after 20-minutes effort:



Good enough to get out and shoot and better, it seems, than the entire time I've had this body since purchasing used. Most of the images were f/16 at the nearest wall to my computer so I could click the SD card out quickly back n forth between the camera and computer / monitor.

I would use some sort of protection over the contacts (even electrical tape) and/or any opening down into the lens, and bulb blow off prior to normal remount. I think this a legitimate concern with modern lenses. Look at the camera end of your lens and let your imagination help you DIY a solution. Perhaps a cheap lens cap with center cut out, if nothing else, would protect the entire end of the lens. Let your DIY-ness prevail!! Imagine if if touches some dirt, goo or worse....don't want to remount without inspection....