3D Model Issues

Within Cesium, our team loads in 3D Models (.glb), and we have been running into some issues.

Is there an easy way to rotate a 3D model on its local axis? My team tried using orientation callback, converting it to HeadingPitchRoll, adjusting by 90 degrees, and converting it back, but no luck.

Not to mention that 3D models appear much better in Microsoft 3D viewer than in Cesium. Would you happen to know if there is a quality adjustment?

Lastly, loading in 3D Models takes a long time. It could very well be an internet speed issue, but I was wondering if there was a way to optimize this.