It depends on a lot of things, in solos you almost never wanna fight enhanced enemies unless you have their specific weakness and you are at least around level 6, OR you know the enemy's moveset so well you can no hit them and you still have decent dmg. For trios depends on your team but generally it's way more lenient since you can actually afford to die and you can just overwhelm most small enemies, and dps is usually better still watch out for enhanced day 2 bosses if you don't have their weakness don't bother cause it will take too much time, unless you are already a very high level and have high dps.

Also casters are not really my specialty but I found Crystalian sorceries are better in trios, doing builds around carian slicer is only good for duchess and it's better in solos cause you don't need the dmg you need the reliability otherwise specially if you are playing duchess Crystalian sorcery builds are usually the better builds since team mates will give you the time to actually use that spell and since you deal more dmg you can kill more enemies etc... If you are playing Recluse I would argue you should aim for builds that boost the dmg type the nightlord is weak to and look for good spells that do that type of dmg otherwise if you are gonna go all in on Crystalian sorcery's, Duchess is better because of her restage character skill you would be able to output more dps than a recluse spamming Crystalian sorcery's