I tried adding Black Squad as a OW game with the root dir + i tried all subdirectories. None of the worked. So my question is: What does OW expect to find in that dir to consider it being valid?
Did you try to launch the game directly?
While it IS possible to add games manually to overwolf’s detection, the game should be detected automatically as soon as it’s launched for the first time.
If that still does not work, would you mind sending us your logs from after you tried launching it? (store → top left → support → generate logs)