Kindle Oasis (2016 version) Replacement

My first gen kindle oasis is starting the slide into obsolescence. The battery used to only require a charge once a week to keep up with my reading, but in the last 6months or so I've had to start charging it twice a week. Not a huge deal but it does mean that the degradation has begun in earnest. Plus, I'm not a fan of charging my eink reader multiple times a week. It should last, blast it!

So I'm looking for a replacement. My biggest "must have" is buttons. I am a button guy and will accept no ereader that doesn't have them.

I do use calibre to manage all my data and it is drm free, so that shouldn't be an issue.

Right now, I am favoring either the Kobo Libra2 or the Kobo Sage. Anyone have any thoughts on if the extra money for the sage is worth it? I read novels and that's about it.

I'm open to other brands and models as well.

Thank you for your time.