So anyone know a way to resolve this? I'm doing 2 of the missions where you have to defend mortar upgrade, and all my enemies spawn right in front of the objective. Then I end up either getting objective destroyed because they just surround it, kill too many civilians because I place mines and c4s, or I die. I've been going at it for 2 hours now can't get it, other ones where enemies spawn farther it's some what manageable, but when 10 spawn on top from all sides, and they don't miss on hardest difficulty, seems a bit absurd.

I also read about blocking with cars etc, does not work they do not miss me nor objective, and they are literally I see them spawn like 10 feet away not even and start shooting at it or me, and again, if i'm in the open I die with 2-3 hits, if i'm in cover objective gets destroyed in 3-5 seconds, and blocking does nothing.