But … why then do the whole spiel with the VR game where they tell humans about their existence and plan to come to Earth? Seems contraproductive if their plan is to halt human advancement.
Because they're not telling everyone, just the faction that they recruit as a fifth column to sabotage human progress from within. Invaders need local allies to unlock the door for them.
And I still can’t get over the fact that they want us to buy that in decades of talking to the aliens the concept of lying never came up. This is perhaps the single most unbelievable thing in the whole show and a total WTF moment when it happens.
Not the concept of lying so much as the concept of hiding their thoughts from each other. Their form of communication is directly brain-to-brain, essentially telepathic, so all their thoughts are constantly exposed to each other. So the idea of deceiving each other never occurred to them. It's literally impossible for them.
Also, are they really talking to the aliens all the time or just to the Sophon AI pretending to be the aliens?
In the book, the sophons are AIs that they've sent ahead as their proxies. The AIs can travel at relativistic speeds that the crewed ships cant, so they got here hundreds of years earlier and started laying the groundwork. At least in the show, it seems the San-Ti are being presented as a hive mind -- "If one survives, we all survive." Presumably the sophons are part of that shared consciousness.