Horrible performance to render a large gltf file (11M faces)

[Evgeni_Popov]

It seems that this is a known shortcoming, at least for the inertia:

Camera inertia doesn't scale properly based on framerate

Hey, I just wanted to reply to this saying that this is currently something that we’re actively looking into. It make be a bit before we can address this so I’ve created an Issue to track its progress: Modify Calculation of Inertia to Scale Based on Frame Rate · Issue #12820 · BabylonJS/Babylon.js (github.com)

Maybe you can try to adjust camera.speed based on the delta time with the last frame (engine.getDeltaTime())?