How to connect from...

Hi all - really need some ideas on this:

I have a Hawklock Advanced Cage Kit for Sony a7r VI, with a monitor mounted by Magic Arm with dual ball heads (3/8-16 Arri to 1/4-20).

What I want to add to this, is a swivel and tilt monitor mount, so I can quickly change the angle of viewing while shooting. I cannot figure out how to securely attach the 1/4-20 of the magic arm to the mounts SmallRig has.

I would really love the ability to have a quick release by NATO. What parts do I need? What have I done wrong?