Translated story part 2

The design of her team was almost done, but her rival, Marcos, always hadwas a step over ahead.

Step over= go above something
step ahead= has advantage

One night, she discovered a strange malfunction in the system and she suspected in a sabotage.

However, instead of panicing, she took a deep breath to soothe herself and worked for a late timuntil late to fix it.

Soon, she heard Marcos admitting that he sabotaged toby penetrating their code.

With a quiet confidence, she reported him, and justice was achieserved.

This is correct, but it would be more natural to say "justice was served."

The victory, achieved with integrity, was much sweeter than revenge.

this is very true

Emma felt overwhelmed by the stress of the next robotics competition.

"robotic" is an adjective. "robotics" is the noun.

The design of her teamHer team's design was almost done, but her rival, Marcos, was always had a step ovahead of her .

If by "team" you meant her robots, your original sentence is correct. But if by "team" you meant her teammates working on the same project, "Her team's design" is more concise and natural.

Also, "(be) a/one step ahead" is a set expression.

One night, she discovered a strange malfunctionbug in the system and she suspected in a sabotage.

You may omit the second "she" so as to avoid sounding too repetitive.

However, instead of panicking, she took a deep breath to soothe herself and worked for a lateong time to fix it.

In tThe next day, her team presencompleted the presentation perfectly.

Soon, she heard Marcos admitting that he had sabotaged tohem by penetrating their code.

With a quiet confidence, she reported him, and justice was achieserved.

You may also write "With quiet confidence".

The victory, achieved with integrity, was much sweeter than revenge.