I've played 3/5 games on this poll (both Xenoblades and Octopath) so I can only speak for those:
Combat: Xenoblade 2 is the clear best. Really great combination of action and strategy. Octopath's battle system is alright, but in normal battles it revolves heavily around "try every move type until you discover their weakness, then keep hitting them with their weakness" which I find pretty tedious. I didn't really like Xenoblade 1's combat much at all.
Characters: Xenoblade 2 wins for me. 1 probably not far behind. Octopath's characters are fine, but they hardly interact with each other, or really do anything outside of their own stories, so there was a lot of missed potential.
Story: Xenoblade 1 by far. The story is tightly paced, and you constantly want to see what happens next. To date it's the only game I've ever played that made me both want to stay up late and wake up early because I couldn't put it down. As for Xenoblade 2, it's very... hit and miss. It has a lot of great ideas, but it's also weighed down by shoddy voice acting, reliance on anime tropes, and some cringeworthy "humorous" scenes in the early game. I would say it's more good than bad but there's a fair bit you have to tolerate. As for Octopath, I didn't finish it so I'll refrain from commenting.
World building: Xenoblade 1 wins here. 2's worldbuilding is ambitious, but maybe a bit too complex - it throws a lot of concepts at you and relies on some less-than-seamless exposition scenes to get it all across. Octopath is much more generic.
Aesthetics: I dunno. Why don't you look at some screenshots and decide for yourself?
Exploration: Xenoblade 2 by far. In fact I'd say it has the best exploration of any game I've played. Xenoblade 1 is similar but not as good as 2. Octopath, being a 2D game, is much more limited and exploration has a relatively smaller focus.
Enemy design: Xenoblade's enemies are generally just fantasy animals. There's not much to say about it. I can't remember anything about Octopath enemies.
Overall best JRPG: Xenoblade 2. Xenoblade 1 is pretty good as well. I really don't think Octopath is that good.