Welcome to the world of too many pixels on too small a sensor....

And yes it is pointless - unfortunately the marketing nerks insist on using ever more massive pixel counts as a way of conning the gullible in buying the latest model........

I try to use mine on ISO100 as much as possible and save the files at maximum quality. I would also suggest that you set the colour mode (Record menu Page 3) to natural - standard isn't too bad either but avoid Vivid etc. as the in camera processing makes everything worse. I do occasionally use mine at ISO200 (and even 400, though only when there's no other choice) and find the result acceptable.

I must admit I'm pretty happy with mine, within it's limitations, and use it quite frequently. I don't find mine as noisy as you seem to be getting though, here's a typical example and another and one more...