In the past I have cleaned many FF camera sensors and it was not that hard. Now owing panasonic G9 and G9ii cameras they have a “Floating” head . Not fixed as in nikon DSLR D810 for example
So a slightly little different technique I had to use so as not to put it out of line. this is what I used to remove a stubborn bit of dirt
first of all I tried the round swab to see if hat would shift it but it didn’t. So next was a wet wipe. The trick here is to put a drop of sensor fluid onto a surface and dip a round swab into it. This way you don’t flood the swap and drown the sensor. Next with the round swap gently wiped over the dirt patch which removed it but then left a smear across the sensor. No panic, just using the spade m43 swab size to gently wipe almost all of the smear away but not 100%. This is where the soft sensor brush comes into play. by brushing across the sensor lightly the slight smear gets brushed off making the sensor back to 100% clear.
In the past I have also used a loupe to examine a sensor but was not needed in this case
So anyone with the same issue I hope this helps a bit