Creating half-cylinder walls in a mesh I am new to blender and am having trouble inserting &quot;inward beveling&quot; the walls of my mesh.  I am using 2.91 of Blender.
I have the walls defined - below:

I am using cylinders as templates to create the arc I want in the primary cube. I want to now &quot;cut out&quot; the cylinders and create new walls aligned to the edge of the cylinders where they intersect and bevel inward on the primary cube.  Then I need to add some thickness to those walls.
Here are images from the top of the primary cube and bottom so you can see the vertex.


I have tried the boolean modifier but it does not create the inner wall - it just removes from the faces that the cylinder intersects with on the primary cube.  And I am having some issue there where it's not delete anything from the top face (the one without the extrusion).  It might be I need to add a grid fill to create more faces.
Any help is appreciated.
Another solution using vertex bevel.

Add an edge top and bottom (for now you can F a temporary face for your object, it will be deleted later)

Select the vertices that define the edges and press Ctrl + Shift +  B followed by P to change the profile.




Hide everything except the bevel you just created with H

Alt + Shift select and use Bridge Edge Loops to complete the shape on each side