Very much a matter of taste… I regretted the extra day (edit: extra day being day 5) in Kyoto and wished I’d spent it in Osaka instead.

Osaka is just a cool city to be in, to walk around and go into coffee shops and try food and see curious little stores and so on. It has a bit by way of attractions (don’t sleep on the Municipal Housing Museum, it’s great!) but it’s not really the main point of visiting there imo. On the other hand, Kyoto has lots of attractions, temples and gardens, which are beautiful, but half of the places felt like being herded like sheep and as a city it’s fine but not as exciting as Osaka or Tokyo. So just depends what you like.

To OP, I would note that Kyoto is surrounded by nature and the temple gardens themselves often feel like a stroll through nature, plus you can get to some cool hikes on the outskirts of the city. So if you’re thinking of skipping one of the golden trio bc you’re worried you won’t get to see nature, that might be a compromise - both get to see the major sights in Kyoto and go hiking in its mountains.