Yup ! I tried it on the * and p tag but not (why the hell not ?) on the body.
90% of the time the epub hyphens are correct, but I notice an issue with the non-breakable spaces and the horizontal ellipsis (and in french they are heavily used for one is needed in front of ! ? ; etc. which is not so visible in english I think).
https://www.mobileread.com/forums/sho...6&postcount=36
Anyway : adding soft hyphens + body {adobe-hyphenate: explicit;} in kobo_extra.css is a great combo
Thanks for the guidance !