Very nice image, thanks for sharing.
Since you moved to Linux maybe you want to try an alternative workflow with Siril and Gimp. There’s a tutorial in the Articles section.
One remark: I wouldn’t expect the sky to be so noisy, considering this is the result from a 35-frame stack, but maybe I’m missing something.
Disclaimer: I did some three or four nightscapes so far, with a very, very cheap equipment, so I’m completely amateur on this.