I'm intrigued that you think Kindle has worse text options than Kobo; in my experience it's the other way around. My Kobo doesn't have the ability to justify just body text while leaving headings alone; my Kindles have handled that just fine for over a decade.

What options does Kobo have for text that you think Kindle is missing?

I use my Kobo for comics and buy those through them (specifically got one with a large screen since Amazon didn't have a similar device), but I don't know if I'd switch to Kobo for novels. I'd rather buy from Kobo and sideload to my Kindle.

With my Kobo Libra 2, if I set justification to "off", it follows the justification that's in the ebook -- which usually tend to do exactly what you're asking, e.g., justify body text while leaving headers alone.

When I switched over to Kobo a few years ago, it seemed much easier to manage custom fonts, too, although I think Kindle has improved in that regard. I don't think there's a tremendous amount of difference between the two in practice anymore, though. (In terms of text handling, that is.)

Unfortunately many ebooks don't specify a default justification on their body text, so with "off", my Kobo Sage will left-align the text in those books.

Agree that I think Kobo better manages custom fonts from what I've seen. (I don't use a custom font so I'm not 100% up-to-date on the sordid details for either platform.)

Line, paragraph spacing, fonts and font sizing and margins. Amazon has like 6 options of each. One of which I consider almost tolerable (but not quite) and the rest are useless. Kobo has a LOT more play with these settings and much easier to get something I like.