^^ by forced I meant more that the game banks on everyone played Honkai Impact and know these 2 already. It skips over introducing them and just makes Seele act mean to Bronya for no reason at the beginning. Then out of nowhere she's super caring and they have a love/hate relationship. I guess it's like you said, they aren't fleshed out enough. It's honestly my biggest complaint with Star Rail. The character writing is good but the story writing isn't that great.
I wouldn't say Eula x Amber is a real ship. Not only is there a clear age gap, the game also very clearly shows their relationship being sisterly. If anything based off her teaser and drunken rant at the bar the game ship teases Lumine and Eula. If you look at Lisa/Jean, Dehya/Candace, or Ei/Yae the pairing of Eula/Amber has much more of a family feel.
Stelle x March also have way too much chemistry to be replaced. The only replacement would be Stelle x Asta.
I hate this ship with a passion. It's a insult to yuri fans. The only confined lesbian in FGO is a gag character that's in love with one of the most het servants in the game. The biggest middle finger to yuri fans