Sliced up the original model in a different way to try to eliminate the long seam. It had the added side effect of making the outside smoother as almost all of the steep angles are removed as well.

Use supports on the non-handle pieces.
They will be tiny but it helps with the appearance of the remaining steep angles.
The steep angle on the inside of the model doesn't matter as it won't be visible.

I used 15% gyroid and it feels very solid.

You may need to scale the pin to fit depending on your printer.

Bambulab blue grey is a great color for this one.

Print, press together, enjoy!