Yes! You may end up in the same games as players on Xbox, PC, Meta Quest, iOS, and Android!
For balancing reasons, you will either get matched with other screen players if you play on screen mode. If you use PSVR to play Rec Room, you are more likely to get matched with other VR players.
If you would like to opt in to only playing with other PlayStation players, you can find this option in your watch menu > Settings > Advanced. However the only people you will find in this mode will be other PlayStation users who have selected this option, which will likely be a much smaller pool of players.