The /Unreal node will auto level the output to ready it for Unreal Engine.
The bigger issue here however is that round tripping with UE isn’t really that practical for this workflow.
You can attempt it
Just be aware of Unreal’s remapping requirements every time you go in and out again
You can see here the manual method to see how unreal will remap -256 > 256 range, you must essentially do this process backward.
The other is that unreal resolution is lower than the typical power of two.
You would be reducing the quality of the resolution every roundtrip.
You can build a Gaea workflow that reintroduces quality every time, just be aware of these things
For remapping the auto level you could potentially use /match node as well