Well, since you're asking, here goes a bunch of portrayals of Childe with playable characters as well as other interactions with npcs since I don't understand why you want to exclude them for no reason:
-Crystallina Chapter, where we explore deeper Skirk's character and we are able to see why is it that she seemed to push Childe away, said reason being that she doesn't want to put Childe in danger of her master Surtalogi and that she does indeed think he's strong and has great things in his path.
-Ignis Purgatorius Chapter, with Arlecchino and the Traveler and said to have had fun with other of the people of the Hearth, who aren't all children. Arlecchino talks about how he's a kind person but he has great potential to be a harbinger nonetheless, as well as solving their internal conflict as it was due to the influence of Pulcinella.
-Monoceros Caeli Chapter, with the Traveler and his subordinates which seems to have a good friendly relationship.
-Labyrinth Warriors, with Xinyan and the Travelers.
-Outside the Canvas, Inside the Lens: Greenery Chapter, with Yoimiya.
-Liyue AQ, Act I: Of the Land Amidst Monoliths and Act II: Farewell, Archaic Lord. Even if you don't want to include Act III: A New Star Approaches despite the fact the traveler and him ended up in nice terms. Having fun with Zhongli and the Traveler. Zhongli even speaks highly of him in his voice lines.
-Fontaine AQ, Act I: Prelude of Blancheur and Noirceur. Act II: As Light Rain Falls Without Reason. Act III: To the Stars Shining in the Depths. With the Traveler, a nice interaction with Navia, a lot of friendly npcs who seem to adore him. Neuvillette doesn't seem to hold any I'll feeling towards him at all, the opposite is true and Arlecchino is made sure to return what belongs to him since they are good colleagues.
-Natlan AQ, Act III: Beyond the Smoke and Mirrors, where Capitano talks about Childe showing us that he does value his thoughts and opinions even in casual conversations as a proper colleague.
-Nod Krai AQ, Act VII: A Traveler on a Winter's Night, where Arlecchino and Childe have a friendly conversation, keep each other up to date with the relevant information. As well as the information we are given that Childe too attended the tea parties with Capitano.
We also have of course each birthday mention and the web events like Stone Harbor Treasure Journal where he's having fun with Zhongli and the Traveler once again.
As a last appetizer, Yelan shows us that the man we are introduced to with Childe, who he beat and robbed, was imprisoned for wrong doings, showing that he's not only capable but still will choose to act out of principle and for good within his moral code.