Well, unreal itself have no problem with +/-180, it’s because the eular rotation angle isn’t translated well especially implemented in ways or rotator, all while no other source or access to quaternion ops.
There are something like combine rotator/negate rotator(and maybe some recent ones?) that uses quaternion internally, you can also save results to a transform(which you can then just do transform matrix manipulation(I think again are pretty limited).
If you search for keyword quaternion you will see that this popped up from time to time and still Epic think that those are too hard to break apart and put together back.
Well, the thing is, any sane people would use those quaternion ops to do rotation instead of rotator like break and make.(like Houdini VEX have pretty good quaternion support in node graph editor, I don’t see people complaint about it being too difficult.)
If you want, there might be people like Rama doing plugins to expose those advanced blueprint nodes.
Or if you want to stay stock UE4, you better change your thought path on rotation, use combine instead of numerical add/substract, this way you also don’t have to deal with float point error, as combine rotator automatically does that for you.
(which is the whole point of doing quaternion ops anyway so you don’t need to deal with all these.)