Thanks for the replies....guess I am not conveying my issue very well....
The inside of the block needs a circle appliquéd to make the center of the block. The white pieced diamonds leave an unstable perimeter, and my circles get wonky if I try to make sure the white points do not get compromised. I have staystitched them, but it doesn’t really seem to help. Maybe I can baste some fabric to the backside of the sunburst, applique the center circle through the additional layer, and then cut the added fabric away from the back side.
Thanks for letting me think out loud! I am probably making this more difficult than it is.