@bogdansuprun The main reason why we compress texture is for download size, not really performance.
In any case, we are not using native GPU compression because the quality is not enough (on the supported format by webgl).
By "browser native", we mean the browser not the GPU.
That being said, we still think it's worth it to do it for normal map, but we are currently not working on it, as we have other priority task in our roadmap.
For now you can add "?imageCompression=0" to load the original textures (but you can't save this settings).