So you're complaint is that you had no idea that Mariupol had fallen, then admit you don't follow mainstream news. So how was mainstream news supposed to inform you? Telepathy?
I agree that at all times, and especially during war, you have to be very careful of what is reported, but that isn't necessarily the fault of journalists. War zones are dangerous places, so their movements are likely to be heavily restricted and thus their access to information limited. How can they report on what the Russians are up to when the Russians are hardly going to go around telling everyone? Then you've got the spin each side wants to put on it. The steelworks for example - if official sources have told then it's an evacuation then they have to report that. If the Russians call it a surrender who to believe?