If United is convinced Axel is the future CB of United for decades, it's goodbye to Smalling and Bailly because he can't play as LCB, he's best as RCB where Smalling and Bailly play that role. Lindelof and Jones are capable of playing as LCB even though their preferred position is RCB.
Ole made comments about Greenwood and Garner's playing time, I think they'll get a lot of times next season, to learn and mature so we can see in a couple of seasons we could have Axel, Dean Henderson, Greenwood and Garner in the squad, some of them are possibly the first starter. An exciting time for our academy.