Hello! There are totally charms giving boosts to both magic and melee, most come in the late (lvl 40+) game, like
[Earthfury] but some earlier are already available like
[Battle Preparation]. Also going Summoner is indeed the best path if you love Earth.
Now understand that if at the max level Earth is a viable strategy, during your progression there will be levels at which Earth will be weak compared to other strategies. And dungeons also tend to require you to be able to use very different strategies in order to progress, so if you solely focus on Earth charms and skills, you'll be in trouble.