I tried
add_filter( 'jpeg_quality', create_function( '', 'return 100;' ) );
and also
add_filter( 'jpeg_quality', create_function( '', 'return 10;' ) );
but it generated the same images with the same datasizes.
And file with name “-scaled-484×600.jpg” has not been generated. No idea, what generates this size. Any idea, how to find it out?