How much did the Zoya Group know about the origin of Ren's Genomancer powers?
Ren felt the Zoya Group might have investigated his background. Therefore, they must understand that even though monster gene fluid is sold both officially and illegally, Ren didn't have the money to buy it.
This meant the only way for Ren to obtain monster gene fluid was by stealing it or finding it. If we talked about theft, that was something difficult to do.
For most people, monster gene fluid was valuable, so it couldn't be stolen easily. Besides, it wasn't easy to find a target to steal from. Therefore, it was almost impossible for Ren to steal monster gene fluid.
Now the only way was to find it. But once again, it wasn't easy for someone to find monster gene fluid; it took a lot of luck to find it.