My "Frequently Visited" sites feature doesn't seem to list all my frequently visited sites

My "Frequently Visited" sites feature seems to list a weird selection of frequently visited sites. I've used Chrome, Edge, and Firefox and all of these seem to give a much more accurate picture of which sites I actually visit most frequently.

Perhaps this could be because the Safari version seems to exclude sites which are bookmarked? Is there a way to force Safari to include all sites in this list? Or perhaps an extension that will do this instead?