How do I support negative scale for AR/USDZ? Hacks? #5099

I have a sofa model, and I just flip left arm to right by applying -ive scale. All good in GLB. But then in USDZ it breaks the normal etc.
I could apply scale in blender and make sure all scales are +ive, but then would make the size double, because transforms are now baked in. Another solution could be I keep the negative scaling, and only do the +ive scaling for usdz file? So I use two models?

How would you handle this?