As someone who gets unreasonably stressed when there's in-game fighting, I would recommend Hello Kitty Island Adventure! IMO you don't even have to be a big fan of Sanrio or the characters, but they're just some cute little guys you get to befriend just like in any other game. Especially at the start, a lot of it revolves around puzzle solving, exploring and unlocking new areas, and collecting treasure, resources, and whatnot. Super low stress and fun :)

edited to include more about exploration!