United Club Card vs. Presidential Plus

Hi, longtime reader, first time poster. I have the United Club card, but was interested in knowing if it's possible to change it to the Presidential Plus by calling Chase. The 1,000 PQM for every $5,000 in spend is something that would help me with earning Premier status on United. I was wondering if the Flex PQM earned through the presidential plus was also redeemable in general, or if they are only good for getting closes to premier, and not actual rewards flights.

Thanks!