Better Bend, like every Blender modifier, operates in the object's local coordinate space. If you scaled or rotated the object without applying transforms, the modifier sees a mismatched coordinate frame and produces unexpected results. The fix is simple: select the object, press Ctrl+A, choose Rotation and Scale, then re-adjust the bend. This is a one-time step and the result will be correct from that point forward.

Yes, fully. Better Bend sits in Blender's standard modifier stack as a Geometry Nodes entry and is compatible with all native modifiers. A common and recommended setup is Subdivision Surface placed before Better Bend for denser deformation geometry, and Mirror or Array placed after it to tile or mirror the bent result. Stack order matters the same way it does with any Blender modifier — what is higher in the stack runs first.