Hmm, I think that the texel size should be as you need it to be. I find that Texture Quality is not a good choice of words (on behalf of RC) because it just states that a higher resolution is probably possible. If you don’t need that, then you don’t have a worse “quality” if that value says 30% or lower. It just means your model could provide a higher resolution. The result might be brilliant. If you need everything you can get, then you are probably right. On the other hand you could set the texel size even smaller and see what happens. In the worst case the texels will be represented by more than one pixel in the UV.
I think you are right about the 4K map but I don’t know why anymore - should be easy enough to find with the new search.