New camera - dust artifact problem.

Hello, i've ordered few days ago ASI1600MC-Cool, and have an artifact on image when i trying to imaging.

I cleared my optics 2 times and nothing changing. Glass on camera is clear too, no dust at all. I scared that this dust is on sensor.

I attached images with this bug and i can't do normal stacks with this artifact.

Any solutions here?

it's very hard to guarantee there is no dusts on such big sensor although we already assemble it in clear room

the easiest way would be take one flat and then you can remove it in post-processing