so atelier ryza isn't a game deep into combat/have boss battles?
I would say no, combat is pretty casual. There are boss battles - some of them optional postgame, but difficulty is pretty much determined by how much you choose to synth/prepare.
Right before I recently finished Ryza 1's story, I synthed the strongest weapons I could for my active 3 characters (Alchemy lvl ~50/100). Didn't even bother synthing armor. After an easy final boss, I then decided to just try the optional postgame bosses.. and also beat all of them on the first try.
So that's why I call the combat casual. Not necessarily a bad thing. And Ryza 1 does have one of my favorite battle bgm tracks ever. This was all on the default difficulty, so different settings might provide a different experience.