I'm not much into JRPGs anymore, but I'd suggest Chrono Trigger if you've never played it. It's widely considered one of the best JRPGs ever made, and it's available on Steam.
Unfortunately, it doesn't have a lot of puzzles. Other than that, it meets all your criteria, and it's definitely an Epic Journey.
https://store.steampowered.com/app/613830/CHRONO_TRIGGER/
It's not going to be easy finding a non-action JRPG that's heavy on puzzles. The genre isn't known for that.
Unfortunately, it doesn't have a lot of puzzles. Other than that, it meets all your criteria, and it's definitely an Epic Journey.
https://store.steampowered.com/app/613830/CHRONO_TRIGGER/
It's not going to be easy finding a non-action JRPG that's heavy on puzzles. The genre isn't known for that.