How to change the default compress graphic dialog

I need to compress hundreds of images every day using the compress graphic dialog. Historically, the default setting was 96 DPI. In January 2020, the default setting was changed to 300 DPI – which ballooned the file size of my documents by a factor of 20. What I need is a default value of 150 DPI so I do not have to manually change the compression from 300 DPI tp 150 DPI on each image. I use the Debian version of LibreOffice 7.1.1.2. I have spend days trying to find the file were I can change this setting. I have also searched in Tools, Options, Advanced, Expert Configurations but no luck. On Github, I can see that the settings I need to change are in the file:
core/svx/source/dialog/compressgraphicdialog.cxx
Line 49 and 64 change m_dResolution from 300 to 150.
But I cannot find this file in the uncompressed DEB folder for LibreOffice.

I am hoping someone on this forum can explain how I can change this default setting.