Kaiseki also has variations! There are totally food enthusiasts here which could steer you towards ryokans with extremely strong cuisine and standalone kaiseki restaurants.

It's kind of amazing how some of the smaller ryokans managers/owners are also the (quite solid) chefs in addition to front staff and cleaning staff... Ryokan meals aren't always exclusively Japanese cuisine, either, so I think some travelers hoping for Western options should be looking for those types of Japanese inns which serve fusion or European cuisines. Some may be named Auberge operated as an upscale Western style inn ryokan equivalent with half board, usually without onsen.

Tip - And and and don't forget to eat more fiber! It's easy for traveler's diet to be low on fiber with kaiseki, sushi, ramen, curry, and etc. Hotel breakfasts can be easier to find salad, greens, and some fruits and then eat all the cabbage served to you (popular greens option). Convenience stores do usually have fiber nutritious side dishes in the refrigerated areas and some people like 7/11 make-on-spot green smoothie.

Omakase might mean omakase sushi. Western (social) media tends to use the word without knowing the definition like umami and omakase (chef's choice ... of whatever the cuisine is, not just sushi). So higher end seasonal set menu tempura can sort of be considered the chef's choice. I don't think I'd go to a high end/upscale sushi restaurant in Japan for the first time and start the visit by asking for specific fishes, either, other than stating any allergies. Some ask at the end if you'd like anything additional. Many Japanese restaurants in US use "set", "combo", or bento instead of teishoku, depending on whatever plating they use. I guess I'm not the only one whose wondered about how bento was reverse Engrish'd into Western language but not teishoku. The red and black multi compartment tray seems rather common in US Japanese restaurants.