I have found most of the free public domain books in the Kobo store are poor quality - hard to read, many errors, ...
I now currently start at the mobileread library as they have been submitted by members here. They have usually been formatted nicely and have most of the OCR (scanning to text) problems fixed. I recently tried "Red Badge of Courage" since it fit in with my Memorial Day in Gettysburg trip. Two different free versions from Kobo, one was bad and the next was worse. The mobileread one was very nice. I found only one spelling error and unfortunately, I didn't mark it so it could be corrected. Can't find it now, darn it. Now I am thinking I could highlight the error and store it away, but I didn't think of that at the time as I have never used the highlight feature of the kobo ereaders before.
Highly recommend the following before Kobo freebies and Gutenberg:
https://www.mobileread.com/forums/ebooks.php?forumid=130