A6300 handles noise very well.
I have a ISO3200 photo of a bird, that was approved by SS, and the other agencies I upload to.
One thing you can do to reduce noise, and make sharpness look better, is to resize. If a 6000 pixel wide photo is reduced to 3000 pixels, it looks a lot better.
Yes - if you have a good bright exposure, you can get an acceptable photo even at 3200. I've done it with insects. Really, I have no need for a better sensor, for anything I do. The a6300 isn't holding me back in any way.