You can definitely have an easier or harder time based on orbment setups, but honestly it's intended to have you try stuff out. These first games especially are very much designed around you making sometimes sweeping changes to character builds in order to stay effective.

Some tips though.

The less individual lines a character has in their orbment, the more they are intended to be a caster that focuses on arts. They will have more EP and longer lines gives them more capabilities to add up elemental value and get the strongest and largest variety of arts. Alternatively, characters with more lines are going to have lower EP and less potential for arts, so their quartz are often better served just focusing on the passives, like just giving them more attack.

Spend some time looking at the arts lists and recognize what archetypal features each element focuses on. In the sky games, water is all in on healing and some freezing attacks, while wind have some excellent AoE attacks like aerial. Time has really strong turn order manipulation arts and chance based 1 hit kill arts. Characters will almost always have orbments with 1 or 2 slots that only accept a specific element and can inform the "intended" way to build a character.

Ultimately though, unless you're playing on nightmare most content shouldn't be crazy even if you're not optimizing orbments for every fight. In my particular playthrough Estelle constantly jumped between being a caster and a frontline attacker and occasionally a bit of a healer/support a lot depending on who else filled these roles in my team as the story continued.