How do you get the true ending?
You have to see every scene during your story playthough, then choose to fight the final boss and win on day 91. Scenes are dependent on having specific androids working specific days, sometimes in a specific job, and sometimes you need to have seen a previous scene for it to trigger, which doesn't matter for a True run. Without the text document provided on the conditions, it'd be nigh impossible to do it yourself... but the dev provided them.
At day 9, you need a Purple working in the brothel.
Between day 11 and 31, you need a Bar built.
At day 18, you need a Pink working in the brothel, oh god why would you do that.
At day 20, you need a Blue Deployed.
At day 26, you need a Red Deployed.
At day 31, you need a Bar built.
At day 35, you need a Red Deployed.
At day 38, you need a Blue Deployed.
At day 42, you need a Pink Deployed.
At day 45, you need a Green working in Operations.
At day 59, you need a Green working in Operations.
At day 62, you need a Pink working in Security.
At day 65, you need a Blue Deployed, and have reached level 7 reputation. Why you would still have a Blue this late in the game is anyone's guess.
At day 84, you need a Blue deployed. Green will 'say goodbye' day 75, so it isn't unheard of to have replaced her with Blues for flavor in Operations by this point.