Depends on what sender unit you have. Ducati has tried a number of different sensor and connector designs and changed vendor sources over the years in an attempt to improve reliability. On earlier units, there are two small pinholes on the side of the sensor that lets the fuel in/out. Try using compressed air to clean out the holes.
The float moves without issue. Just doesn't change impedance.
This little project all started when I went to reinstall the tank (on a shelf since winter) and heard something rattling around inside. Finally got it out after trying magnets, tape, three different processes with a shop vac. You'll notice something missing from the body in the pic. Potting departed its home.