Also, I doubt Giga's arsenal would be enough to kill a Shant, especially with a 6 ton difference between them, meaning that Shant is far more durable than the Southern Gigachad.
Shantungosaurus may be more durable, but in relation to each other's weapons specifically, Giganotosaurus would be more durable because its offensive capabilities are greater than Shant's.
"but in relation to each other's weapons specifically, Giganotosaurus would be more durable because its offensive capabilities are greater than Shant's"
That doesn't mean that the Giga is more durable, it just means that it has greater offense.