Quick Answer
Yes, the Acid Lab is worth it for many solo players. The catch is the unlock path: you do not buy it like a normal property. You follow the Los Santos Drug Wars missions, get the Brickade 6x6, then turn it into a working mobile lab.
If you want a clear solo business and you are fine doing setup missions, Acid Lab is a strong option. If you want money to appear with no setup, no missions, and no business loop, wait.