Make the cylinder slightly wider then the gap so that it overlaps, and then decrease its depth by an unnoticeable amount (0.001 studs e.t.c) to eliminate z-fighting
Scale each part towards the center of the circle. Since it looks like you are using smooth plastic @wf_sh’s solution may not be the best solution for this specific build.
If you are using any other material that has z-fighting, their solution may be the best.