Forget what FM says. Saka starts wide and distribute the ball as playmakers do. Is a new role for him but he's doing it well despite the lack of runners near him. And yes, you need runners in the team, but that's not his main job to do.
I don't think White is a IW, really, he's not Zinchenko at all, he stays wide, overlaps sometimes but he remains at the back. At most, you can give him the PI to come to the middle.
The CM-A role does exactly that. It says that "the Central Midfielder will more readily surge into the final third to support the forwards in and around the box". And then, his attributes and PPM will do the rest,
I want to add that I'm not trying to antagonize you in any form, I want to recreate Arteta's tactic too and do it the most accurate possible and I'm using the thoughts of NoNewThing on twitter to came with an better idea how Arsenal operates and translate it to FM.