My impression of the present/near future of air combat is a stealthy fighter with AMRAAMs in front, radar off, and a quarterback aircraft in back out of missile range, with the radar on. The front fighter fires and turns around, and the missile gets mid-course updates from the quarterback aircraft. When the AMRAAMs are depleted, you leave. It seems like if you get into Sidewinder range and you're outnumbered, you're going to have a torrent of medium range missiles coming at you from all sides.
It's not clear to me how well newer radars can track the B-2, but it's hard for me to see how fighters could really protect it. I'd expect that in a conflict with China, if they can track the B-2, that the B-2 would be withheld until the fighter threat was neutralized.