artifacts when rendering volumetric clouds

I’m trying to make a star dome. And I haven’t come up with anything better than just using a huge sphere (static mesh). This sphere has dimensions of about 400,000 km, as there is a natural-sized moon in the scene, which is about 380,000 km away from the center of the world. And when I add volumetric clouds to the scene, they begin to shimmer against the background of the star dome. This problem is solved by the console command r.VolumetricRenderTarget 0, but this command is too expensive for performance. I’ve tried many console commands, but nothing works. On the left are clouds in the background of the starry sphere, on the right there is no starry sphere