I don't know if there is another way, but the way I did it was to modify a couple of jar files following instructions in this post
https://www.mobileread.com/forums/sh....php?p=3272458
I changed reader.progressbar.height to 0. I also reduced the margins to get max amount of text. See picture. Sorry for the blurriness.
It's a little involved and if you mess up you can soft (hard?) brick your kindle
