Will I learn anything from reading Plato, Aristotle and the like? Or should I stick to the stoics?
Yes, you will learn many things.
You should put the Stoics to one side for now, and only read them if you find it helpful and comforting on a practical level.
The greatest texts produced by humanity were written between the 5th and 3rd century BC in Hellas and China. The stoic works from that period are lost, at least for now.