I agree that more interactions between companions, especially after Act 1 would be great. As for activities in the camp. Yet, the games you mention are definitely more linear and fixed than BG3 which makes the interactions much easier to implement. RDR2 does it best, camp feels super alive - but the story is not branching, it’s linear, companions can’t die depending on your choices etc.
Yet, there’s visible difference between camp cutscenes in the beginning and in the end. In Act 3 the only conversation between companions I can remember is
Jaheira lightly arguing with Minsc, which would makes sense as they haven’t seen each other for such a long time and their friendship is anchored in canon, I guess
Biggest problem, when I think about group activities in the camp would be pacing/all the diffrent combinations.
For example let’s say

During one day you rescue everyone from Iron Throne, along with Wyll’s dad, and you do Selune Shadowheart story with her deciding to be free of Shar’s curse. Her cutscene, I imagine, would be first in line and then cut to, for example, playing cards of feasting with Prince Ravengard? Either cutscene must account for mood of certain characters, to not break immersion, or not - and then you can have someone who’s grieving suddenly laughing or whatever. There would be potential coherence problems, and as we can see with terrible state the endings are that would glitch or not trigger

The only way around it would be giving very clear prompt after certain bigger events - if you long rest now, there will be small feast or activity in camp in relation to events that just unfolded. And I certainly expected so ething like that, especially after Act 1. My team done bigger things than that and no party?? Especially felt weird when some characters suggested exactly this. Anyway.

Companions in camp playing or talking with each other - again, cool, would love that. But. Right now player can control other companions in camp, so I imagine it would be really weird, when two of them are doing something or talking and suddenly you take control and stand up, dialogue cuts. Not the biggest problem, but could mess up triggers etc.

Companions romancing each other - totally would be interesting, yet very unpredictable and especially hard when there’s end. Heavy spoilers below
Imagine this - playing as a good hero, rescuing everyone, bonding etc, and watching romance between, idk, Lae’Zel and Astarion.
Totally weird, but okay, then you kill mind flayer Orpheus and Lae’Zel leaves on a dragon leaving Astarion burning in the sun, horrible end for them! Or Selune Shadowheart being with Karlach and experiencing her exploding, being left totally alone. Heartbreaking!

So if there’s romance between companions there would be much more endings that would show up without player’s decision. Maybe it’s not bad, but would require, to be believable, really a lot of work to implement.

At least, for my Tav, being bard and all I was able to play music in the camp and everyone rushed and clapped their hands if I passed performance check, lol. That was something I did after every bigger battle and felt nice.
So for summary - all these additional cutscenes in the camp, would be welcome but should be really carefully done not to break immersion.
Even as it is now, sometimes effects of NPC in your camp are funny like

Mizora standing next to Wyll and Ravengard and thinking how to and when kill the Duke and Wyll telling me quite loudly that first thing he plans to do as a Blade of Avernus is to kill Mizora. Drama! And Lady Aylin just watching them angrily. Lol

Hope the game, which I think is really a masterpiece, will get more additional content, especially in Act 3.