edit: I have added a step file

I printed it standing on the side. I prefered small layer thickness so it was able to print the round sections more easily. I used adaptive layers but it will be noticable on the final print. I used a 0.5mm nozzle. I printed it with 0% infill but instead, I enabled the option that in every second layer an additional inner wall will be printed and adjusted the line width so that the inner walls touches each other. It's important that no gap occurs.

But of course, you can print it normal with infill or even with 100%. Then you will have an massive object which feels great.