lol behold my shock when he got actual screentime in Endgame. (I haven't seen it, but I don't know if I feel like it so I got people to spoil it for me.) I think the most time they've spent together in comics was when Bucky was Cap and Sam was trying to stop him doing anything too stupid under the influence of a) Natasha and b) the lack of Steve-related chaos in the world. So he doesn't know her as well as MCU Sam does, but he tends to like her.