If I'm reading your situation correctly this may be of help:
Here's how I prepared Rtf files wrt to jagged end of lines...
https://www.mobileread.com/forums/sho...0958#post40958
It uses MS Word mass replace to get rid of extraneous paragraph marks in the rtf file.
Also you can highlight all the text (in MS Word) and use ctrl-shft > to increase the font size until it's about 18 or 20 and set it to Arial or Times New Roman. And you can choose full justification to get clean margins on both sides.
Use right click and "font" to see what size some particular highlighted text is.
I am pretty happy with the way documents are turning out that way. Haven't decided whether I like a blank line between paragraphs... seems too spacious, but without it, it seems a little crowded. But no big deal either way for me.