Welcome @gabriel,
Looks like the one from colour-science not AMPAS 
This is great and exactly what you should do!
This is where things become important. It might appear too dark, but do you have a photographic reference of the real-life rock with the chart right next to it? If not, you cannot really objectively say that the rock looks too dark. You might say subjectively, I don’t like it, it seems too dark.
Please do not do that as you will screw up your lighting! Once you have put the ColorChecker or the chart as a unit diffuse object in your scene, you should never ever touch it, it is the anchor for your entire world here and the only thing you can trust!
Unreal, by default, pre-expose/pre-gain the entire image, the multiplier is 1.45, so it is doing what your instinct told you to do and was one correct thing to do!
You should not really do this, I know it has been recommended here and there but this is not a viable working solution. It might help to produce a more pleasing result but it is dangerous as it might/will destroy the texture to a degree and if the idea to do that is to compensate for the View Transform, then it simply does not work and I would really like for that approach to disappear.
Yes, this is normal, as you increase lighting exposure, all the values in the scene will rise, and ultimately some stuff might appear over-exposed.
You might although you need to be careful doing so to not create non-physical values. There are a few albedo charts around, @ChrisBrejon made one recently that will help you here. It would be interesting to know if Quixel/Epic has some colour char shot with the asset, the texture could be processed incorrectly, you don’t really know at this stage.
A good HDRI, e.g. Unity Supplemental Material and/or a Physical Sky.
Cheers,
Thomas