It would be great if you could fix the axes in the Transform tool so that only one axis is rotated.
You have two options:
With transform gizmo just grab the axis you want to rotate only
Or/ and enter a fixed number in transform gizmo dialogue.
This two options were enough for me, or did I understand something wrong?
@Holger_Schoenischka is probably talking about the Transform tool rather than the Gizmo. I personally don’t use the transform tool as I find the results to be too random. I use the Gizmo instead as it’s more predictable as to what axis you are working on.