IIRC, this is the first platinum I got? Or at least the first one I got on the PS4. It's one of the easiest plats of all time. Took maybe an hour after beating the game, since I'd already done everything. The game's great in general.
Dragon's Crown is mostly fun in multiplayer. The single player is pretty boring, so I wouldn't advise going for it unless you have a friend or group.
But also you have to beat it once in single player to unlock the multiplayer lol.
All the stars in the sky are waiting for you.