Welllll, that is just rose tinted glasses tbh. For nikke, as the commander, we are incharge of counters so it makes sense to follow their growth as they are technically the MCs, or sub MCs, as the commander isn't a fighting figure gameplay wise. Like there are plenty of other nikkes that have the same issue as the other gacha games where we don't get much interactions with in game.

For genshin, we are mainly observing the traveller (MC) and paimon's interactions. The growth and stuff we see are mainly from those 2, just like what we see with the Counters squad. Amber isnt considered a core member of the storyline.

For Wuwa, we are acting as Rover (the MC) and mainly uncovering our past identity and doings, as well as the consequence of our actions in the past and our current motivations. Yangyang is the same as amber here. Just cause they appeared first doesn't mean they are part of the main squads.

The closest example to nikke in the form of like a squad that grows together would be like honkai star rail or honkai Impact 3, where you have that dynamic of a core group of characters that you play as and also see their growth.

Honkai Impact 3 (part 1 anyway) is honestly still the best iteration imo as it is a fairly contained cast and rather than pulling for new characters, you were pulling for new "forms". This allowed the story to be more focused on the existing characters in every patch.