Ilovemyride ,
You seem to be asking why the bottom bearing does not fit the steerer of the fork.

It is correct that t bottom bearing does not fit the fork steerer tube, it is not meant to fit.

At the bottom of the steerer there should be a “crown”, it is a taper, often a metal washer or a taper in the carbon, with a taper that narrows at the top.
As the lower bearing is forced down onto this taper (crown), it centers the fork. Notice the lower bearing is also tapered on the bottom to match the taper on the fork.

Hope that helps

Barry

Here give thi a try.