I also agree: limiting screen time in general is at least as improtant as chekcing contents. I can see how easily children would spend their time in front of one, if they had a chance. I myself spent a lot of time with friends who had consoles in front of them (I never had one as a child; my parents did not like them and even at the computer we were not allow to plug in a joystick as my father had the opinion that a computer is no toy). But we also spent a lot of time outsiede, if the weather allowed it, so I believe that it was sufficiently balanced.
I also agree about social media. For this I could not really give an appropriate age. There are even adults that fall into the trap of misinformation, so how should a child distinguish between "good" and "bad" content. Here, I think, a more or less constant supervision and proper education of children is very important. Not only about things they consume, but also about things they share. But this is really difficult.
I would consider TDM as one of the less critical games regarding age. It contains some violence (even if you only knock out guards, in real life this would likely kill or at least properly hurt them, if you use a blackjack), but in general the goal is to avoid confrontations and find non-violent ways through the game. Playing a thief may also be considered critical, but most children know that stealing is wrong and should be able to tell that they are only allowed to do so in the game and not in the real world.