THIS IS

Expensive build, so if u r sruggling and not ahead just buy more blue items like [Icy Coolant]

SO

Sigma have very adaptive items and powers, and it makes him one of the strongest heroes

JUST

Look at ur oponents pick and items and adapt this build like u can pick dmg reduction and early [Zero Gravity] (good against Mei also) against Reins (mb [Weapon Jammer] against rush-hardt), [Shieldbuster] against D.va/Sigma/Zarya etc etc.

SO FAR

I didnt play any full 7 rounds game, so i dont rly know what would better on 6-7 rounds, its on ur research :)