hmm, strange. may be the specific site i am doing is just shrinking and not zooming out. also when i run this zoom out command then it just shrinks body contents, but not changing value of zoom. you can see while click on 3 dots in top right corner of chrome.
anyway i have found a work around, all automated using your plugin and ubot.
1- launching chrome profile
2- once all files generated for that profile then i quit browser
3- update preference file to change zoom levels
4- launch browser again and navigates to specific site.
5- and it works for 50% zoom value now.
6- do