1.

You should pay attention to the English grammar.

"The attack suits the soldier better than defense."

Here's how it works:

"(The attack suits the soldier) better than (defense does)."

The defense is the subject of the second clause. We compare the subjects of 2 clauses here, not the objects.

So атака and защита both should be in nominative in Russian translation.


2.

Подходить requires dative or для + genitive in Russian.

3.

You missed "better" in the translation.

Result:

Атака подходит солдату лучше, чем оборона.