The tiny, tiny pixel pitch on these sensors are not conducive for lower light photography. The “meta noise” that you are seeing is probably just the “normal” (both luminance and chroma) noise that has been amplified by a huge ISO.
Noise reduction is what smooths out details and gives a horrid smeared oil painting look to everything.
You could try one of the 3rd party apps that give you manual control and play with a lower ISO and lower shutter speed, however that’s prone to motion blur of course, from either the subject matter and/or you.
There’s not much you can do regarding low light.
It is what it is. Sensor saturation is what you always want to go for. High ISO is not the answer. That does not make the sensor more sensitive nor does it change the exposure. It just amplifies all the existing noise from the underexposed shot.