And as for me, several years ago, I used this Python tool to export my Kobo notes.
It worked well. And as far as I remember it just outputted a large well-formatted text file of everything. Which would then have to be parsed/separated. I have never finished parsing them.
(But it hasn’t been updated since 2018, so it might be out of date.)
It might be worth considering too, since it is Python, MIT-licensed, and can run locally on your machine, so it could be the basis of a script/tool that could be used with Obsidian directly. The other two options listed so far seem to be websites only?