The number of sprites in this model shouldn't be too much of an issue so long as the user has got a decent CPU. My model is approaching 100 sprites, for context.
Couple more questions then:
- Does this only happen while OBS is open? Does it matter if OBS is broadcasting or not? Broadcasting software does a lot of encoding to make it possible to transmit data, and this is a CPU intensive process. It is possible to lower your OBS's need for processing power by lowering the output resolution and fps, but of course this cones at the detriment of quality.
- What version of PNGTuber Plus are you running on? The newest version has a lot of optimizations that allow the app to run more efficiently.
- If you're on the newest version, what is your FPS limit set to in the app? Turning it down will make the app run more smoothly and use less processing power. A note tho that adjustments will probably have to be made to the entire model's rigging as much of the physics seems to be tied to the framerate.