How do I get the seams out? First time modeling

I probably made a mistake by doing it this way, but I modeled the basic shapes with primitives then did a basic merge to put them together but I still have the seams between the shapes. How do I fully merge without ruining my topology?

Voxel merge.

You may have to smooth the seams with the Smooth Tool…

The higher the resolution, the better the result.

Thank you!