As I was working on it, I had to guess at the shape but I did what I said, above. That is, I made the handle larger than the final piece and used Round corner on it. Then I drew a shape to intersect with it to create the transition at the top. Obviously you would need to use a different shape but the idea is the same.
Two things you should consider doing to make it easier. first, only draw one half of it. It’s a symmetrical shape so you can make half of it and then copy and flip the half to make the other side. And use the Dave Method to avoid creating holes in the surfaces due to the tiny geometry stuff.