Best stop for a one nighter between Osaka and Fukuoka (besides Hiroshima)

Planning an itinerary for next year and I have one night where I would like to see a smaller city in between Osaka and Fukuoka. We'll just forward luggage onto Fukuoka and pack our backpacks for one night. I have already been to Hiroshima on a previous trip and while I could spend more time there I want to see something new.

The big two options sticking out to me are Kurashiki and Naoshima, and I am leaning Kurashiki. But I imagine there may be some other options. Most of the rest of the trip is big cities so my hope is to get a smaller town vibe and I'm ok with slower but hopefully with things to still do and/or see. Something nature-y would be cool as well. I don't need a ryokan stay for this slot, we're doing that later in the trip.

I am mildly less interested in the bigger cities between like Kobe and Okayama but not completely opposed if someone has a sell. I have been to Osaka and Himeji, though I only saw the castle in Himeji. I have been nowhere else west of Osaka (this trip will be my first in Fukuoka as well). I also got a recommendation for Onomichi but haven't looked deep into it yet.

I am also ok to go north as long as logistically it's not too hard to get to Fukuoka the next day. We don't have a time we need to be in Fukuoka by, but I'd like to be there by 5 PM at the latest

by lot183