One star leves aren't "solo" anymore. It is just a leve mob level indicator. 1* is base for the camp (1,10,20,etc.), then +3 for each additional star, +3, +6, +9, and finally +12 for 5*****.

If fighting things your level is too hard, go fight weaker things and just keep killing, it is almost as efficient as chaining your own level plus no downtime if you manage correctly. PUG is one of the easiest jobs to level from 1, if you fight lower level things, the mobs will miss a lot so you can spam haymaker, even concussive makes them miss more.