A Redditor has a solution for the lack of PhysX support with the RTX 50 series: running two GPUs
It's like a bizarre tag team.

With the arrival of Nvidia's new RTX 50 series, we had to say goodbye to PhysX 32-bit support. This is a pain if you want to play older games that rely on the technology, as your performance will be pretty abysmal. Fortunately, a Redditor has found a solution: install a second GPU that supports PhysX and have it do all of the heavy lifting. Genius.