>>3253907You won't save your pictures with Gimp. Trash it and use a lower ISO (not 3200, you madman!), a narrower aperture (without going further than f/11) and a longer exposure time. Use the timed shutter release and a sturdy tripod to avoid shaking your camera, pro-tip is to NEVER extend your tripod legs fully.
Having anything else than a kit-lens and a small sensor might help, too.
>>3253924>I used a "ND" filter in lightroomThis isn't how this work, my man.