that is wrong and misleading. Akash is probably the last SAM using ramjet. Even Soviet union/Russia SAM did not use ramjet after SAM-6.there is a reason for that
View attachment 22398
here is a simple illustration of ramjet。
Air was sucked in and compressed,mixing with gas(of solid rocket fuel),shooting out of nozzle.
that is how thrust come from. at low speed,there is not enough air sucked in, not compressed enough, thus not enough thrust. So a obvious weakness of ramjet sam is acceleration. At first it needs to overcome drag and gravity with insufficient thrust.
Also it is not that effective against an object with high maneuverability: high maneuver cost speed.speed down,thrust down.
So basically opposite to everything you said.