how they were able to obtain my PayPal account information at all--remains a mystery.
Once you subscribe to a service, you basically give them power to charge any amount they want to. To sum it up fast, you are going to lose, you accepted the terms of this deal.
To mitigate future charges, never use a real card for PayPal, use a temporary or a limited card, like free Revolut provides. My online card is limited to $50 and I change it as needed.
republic of Gilead no lawyers in small claims court, maybe I'll move there. Last I heard a "nusiance lawsuit" was $15,000 and that was several years ok.
Indeed the OP might get his money back in a few months or years, but it will cost him, time and money. I actually pay an insurance to deal with nuisances like this, but it is too late for that.
Take a hit and accept it graciously. People learn from mistakes. Yes, it is a fraud, but a court will not prevent further victims, at best it will get on news and people forget it a minute later.