Re: images inserted into LibreOffice
Rescaling text (even downscaling) always softens it, especially when the change of scale isn't too big.
"Pixel size, file size, and resolution are as I want", maybe, but do you want the correct things?
Warning: unless noted otherwise, code in my posts should be understood as "coding suggestions", and its use may require more neurones than the two necessary for Ctrl-C/Ctrl-V.