Is it possible to reproduce Maya/ Houdini target/ point weld operators inside of Blender? Both Maya and Houdini have an operator called target weld (point weld in Houdini) that essentially is the same as Blender's Merge at last operator, but they are done in one step and are continuous until the operator is exited.
Here is a gif from each program to demonstrate the operator.
Maya:
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Houdini:

My goal is to reproduce this behavior inside of Blender, but as far as I am aware, there is only Merge at last, which at best requires 3 steps to complete one weld.
Is there an operator buried somewhere in blender I haven't found, or some scripting solution that could shorten the steps in merge at last to work this way?
3DSMax also has an equivalent Target Weld, but as far as I know Merge at Last is Blenders closest operator. Unfortunately workflow involves dealing with the menu as you mention, making it unsuited for repeated use.
One possible workaround is using Blender's Auto Merge feature. While in Mesh Edit Mode, from the 3D View Header &gt; Options menu activate Auto Merge.
Just combine it with regular Move operator or the Tweak tool, overlapping vertex should automatically be removed.

Having vertex snapping turned on from the magnet icon on top makes it more reliable.
You can also toggle it on or off from the Tools Options from the 3D View Sidebar or Properties Window.