Yes! Ok, I must have missed that because I kept getting those and assumed I used them in battle. I definitely feel like I would be destroyed if I played on harder difficulties. Like do people normally switch out their attack skill bc I've noticed it kinda does this on its own.
At the beginning of the game, you don't have many Artes, so it just repeats the ones you have over and over on the combo set ups. As you learn more, they automatically update the default combos to utilize most of your new artes. Eventually you will have more than can fit on the 4x4 grid.
You will have an easier time if you do tailor your Artes combos to what you're fighting, particularly against bosses, dire foes, and code red enemies. Each attack has 1 or more enemy types it does bonus damage against as well as an elemental type. Matching up to enemy weaknesses makes a huge difference in how much damage you can put out. On Normal difficulty, you can probably get away mostly with using the defaults.
Just know that for example, Velvet's default combos never used her Hidden Artes, only her Martial Artes
(There's 3 types:Martial (physical), Hidden (lower of physical and magical stat respectively for both attacker and defender) , and Malak (magical) Artes.)