I was going to recommend Suggest Projectile Velocity as well… If all you need to know is what vector to launch a projectile at to hit a specified destination, it’s really just simple math, and the SPV node wraps that math up in a nice little package.
Where this can get tricky is how “smart” you want the mortar to be. For example, do you want it to attempt to adjust this velocity to a lower-angle-higher-force alternative if the original trajectory is blocked by something (like a cliff face or building)? That starts to get more complicated, because then you have to trace across the trajectory looking for blocking hits before actually firing, and may have to recalculate…