Your T1 has pdf text reflow that is much better than how Kobo handles pdf format books. Fiddly is good description.
Kobo readers use Linux OS and unlike Sony does nothing to prevent you from installing other reader software that might be better for reading pdf books.
https://www.mobileread.com/forums/forumdisplay.php?f=247
https://www.mobileread.com/forums/sho...d.php?t=226456