The 2022 Game Awards trailer ends with Batman giving his signature line: "I am vengeance, I am the night, I am Batman!" ...voiced by the late great Kevin Conroy, followed by a graphic reading, "Thank you Kevin." Rest easy, friend.
The entire introduction to the Hall of Justice is remarkably wholesome, with holograms of the League giving introductions to the exhibits for schoolchildren.
Superman's introductory hologram specifically gives glimpses of the Man of Steel at his best: kind, compassionate, and kinda adorably goofy. After dorkily explaining his alien origins as if it weren't common knowledge (he whispers it to the visitors as though it were gossip), he declares Earth a "beautiful blue planet," the Kents as "really nice people" who adopted, raised, and accepted him despite his alien nature, and declares all the Justice Leaguers his friends (yes, even Batman), capping it off by encouraging the visitors to always watch out for others. Which ends up making it a Tear Jerker knowing that Brainiac would corrupt such a sweet, good natured man into his pawn.
The Batman Museum shows just how much the people look up to him. Given that it recounts the events of the four Arkham games, it confirms that all of those actions happened and how people remember him, as a true hero.
The confirmation that Bruce faked his death at the end of Arkham Knight and eventually returned to publicly join the League despite his identity being revealed removes much of the bitterness from that game's ending.
Again, all of this just acts to twist the knife as to how far the great heroes have fallen.
Amidst her valiant efforts to be the Voice of the Resistance during Brainiac's invasion, Lois Lane will broadcast a message specifically to Superman, trying desperately to get through to him and convince him to fight off Brainiac's control and save them. There's no way of knowing if Superman actually saw the broadcast (though with his Super-Hearing it's a fair bet that he heard it at least), but it's quite a touching message, even though it doesn't seem to work...
Lois Lane: Superman. I don't know if you are watching this. I pray that you are. Whatever Brainiac has done to poison your mind, whatever he's done to make you turn against us, and whatever violent impulses spur these destructive acts, I would ask you to take a moment to look inside yourself. This isn't you! Fight him! Fight the corruption! For years, you have been Metropolis' greatest guardian and a friend to all who live here. You've protected us, supported us, inspired us, and helped us grow. You have been a beacon of bravery and strength, a role model to children and adults alike, and the most compassionate and empathetic man I have had the privilege to know. I don't know how Brainiac did this to you, but behind the corruption I know some part of the old Superman must still exist. Please... find him again. You don't have to do this to your city... to your home... to your loved ones. I know how often we've called you to fight for us, Superman. We owe you a debt that can never be repaid. But we need to ask one last favor of you. One last fight. Stand up against what you've become. Stop what you're doing and return to us. We need you now more than ever. Please... Please fight him for us. This is Lois Lane... signing off.
While the Flash is eventually captured by Braniac and becomes just as evil as the other Leaguers, in the time that he had his own free will, he constantly urged Suicide Squad to get to safety, rescued them from being captured and potentially turned or killed by Green Lantern and his final heroic act involves him saving Harley from getting shot by Batman by using his speed to move the bullet just enough for her to dodge it.
Harley responds to King Shark briefly becoming a Green Lantern with a So Proud of You moment.
It turns out that Lex managed to clone Poison Ivy as a little girl, she's still a supervillain and is even less human then ever before but is also quite adorable.
Listening to the ARGUS tapes you can hear how much the League were a solid group of friends, even managing to help Batman grow out of his stoicism.
Bruce's last message to Tim left tears in my eyes.
Even the Leaguers deaths in a twisted way can be seen as this. While it is deeply upsetting to have to kill some of the greatest heroes in the DC Universe. They all most likely would have preferred to die than continue to be made to harm and kill innocent people. So the Squad really is putting them out of their misery in a way. (Even if the Squad isn't doing this for those reasons, nor do they particularly care about them or their situation)
you can hear how much the League were a solid group of friends, even managing to help Batman grow out of his stoicism.