Hi, last post here Get Random Point in Navigable Radius (Can this be forced into a cone?) - #5 by TheFlow3k
So you could just get a random point that you allow (in your 90 degree cone), then check whether that is navigable by using “ProjectPointToNavigation”, repeat until you find one or have enough iterations and assume there is none.
Or you could also use EQS (cone generator), AFAIK the parameters of the generator can be made variables and then you can randomize them.