Thinking in 2D screen, rotating around Y (left-right) and rotating around X (up-down). Something handy would be to use View->Aim or View->Highlight Aim [A] to define a temporary centre for the camera actions (the Look At point). Just select an object element and hit "A" to ...
work in Cesuim with glb is really have little described and mysterious - for example, auto-rotate meshes or the ability to rotate them - that’s still understandable - BUT why can’t I rotate nodes (for example, Empty from Blender are converted into nodes) from a .glb file? As example ...