Pimax headsets like the 8K+ or 8KX have two audio jacks and the Oculus Quest In-Ear headphones are designed to go into each jack of the Quest. So I’m guessing they would probably work with Pimax too.
When I used to own a Quest and tried these earphones, the sound was very good. Deep bass, quality surround immersion. Sound was somewhat close to the Valve Index. I think they would be a good accessory to use while people wait for the Deluxe MAS?