This really important but being hacker doesn't mean you gott have skills in gaming. So even though she might be genius hacker then there is also this fact and high possibility that she can be really suck at gaming so my of course goes to Hana. Even best AI's of the period and Omnics doesn't beat her into defeat when it comes to competition in Starcraft or in other war gamesç Mind you she is making real life frags with her Meka too lol.
You're assuming Sombra wouldn't cheat her ass off, and she totally would.