No fault of the game but I just couldn’t figure out if I wasn’t leveled enough or lacked the skill.

Even the hardest boss in the game can be killed with one shot on normal difficulty with a correct build and the right turn order.

I say that because while learning how to parry and dodge are important, pictos and equipment can more than make up for inabilities in the middle-to-late game.

Overall, pictos are arguably the most important thing in the game.

I wound up playing the game through twice, once on normal difficulty and then again on story difficulty (I just really enjoyed the game and wanted to 100% it and had missed a couple of the only missable achievements).

Don't feel bad playing it in a lower difficulty level, and then try to learn when to parry attacks. There are often visual and audio cues.

A lot of the difficulty when playing the game as intended (at normal difficulty) is learning the pattern of when to press the parry button. You can learn this more easily on story mode because it's more forgiving. Counterattacks are very powerful throughout the game, and only happen if you learn how to parry.

Maelle being powerful also has a lot to do with the weapon she wields. If you didn't beat the last Gestral arena fight with Maelle, you might want to restart the game and do that, because that weapon will carry you all the way through the regular end game (though you might need a better weapon to 100% the game).

You can beat the main story using Lune's abilities for your main damage pretty easily. The one-two punch that I found very useful (after building around it) was using "Elemental Trick" followed by "Elemental Genesis". With Elemental Trick, you can produce 4 stains in a single attack if you get your critical rate up. One easy way to make critical high is to use the Critical Burn picto and make sure to keep around a burn on one of the enemies to attack with Elemental Trick. Once you have the stains you need (4 critical hits, one of each element), Elemental Genesis can one-shot a lot of enemies throughout the game. It's great because it's a multi-hit attack and a multi-enemy attack. It works very well before you can do over 9999 damage in a single hit.