It's been a bit since my last post.
I've been definitely discouraged by the amount of math I keep struggling with, then work and life in general didn't help but were lazyness and being out of my comfort zone what really kept me away of my project.
To be honest a few weeks after my last post I came to know of a specific blueprint node that just does the job, it's called “Line Plane Intersection”, you basically input both a start and end point (vector's) and an origin and normal for the plane then it just outputs the intersection coordinates and another couple of values. I know it's a lame way to do stuff but in my case it really helped.
I just fed the output coordinates to the character and that's it! Now he happily moves to the point of intersection.
The "code" needs to be refined in a sense that the character moves only if there's an intersection and not there's none, IE: the projectile is going to bounce off a wall first.
So I should, as soon as the projectile is fired, calculate the trajectory after the bounce, if there's any at all, and use that instead.
I'd like to thank you again Thaumaturge for pointing me in the right direction.