Merge two radial shapes with clean topology

Question

I am working on a joint which look like this. I would like to join the parts in a spherical fashion with the faces that I indicated with green marks. This type of problem keeps coming up and I don't know how to deal with it while keeping a decent topology. Is there a fit-for-all kind of solution for this?

I use Blender 3.5, here is my blend file as well.

Answer 1

First thing remove these faces (including the inner faces that should not be here):

Select these 6x2 edges on each part and CtrlE > Bridge Edge Loops:

Tweak the parameters in the Operator Box (Number of Cuts > 2, Smoothness > 0.6):

Do the same for the outer faces:

Fill the holes: