Yeah, I know what you're trying to do.

Try leaving the Polaris connector connected so you don't crush the adapter, and then use a pair of channel lock pliers on the adapter if you can get to it. Sometimes they are screwed in so deep that they are inside the face of the pool wall. You may have to destroy it to get it out.

In our shed that came with the house is a Polaris connector solidly connected to an adapter. In the pool is a new connector/adapter, so it appears that the previous owner gave up trying to get them loose. For some reason these plastic parts seem to weld themselves together over time.

TW