At the moment their is no easy way to insert nodes between a current connection without cutting the cords and reattaching them with the new nodes. A workaround is to connect all nodes which creates simultaneous connections and can have some unintended consequences, as seen below
What would solve this problem is to have easy code insertion. Inserted nodes would be connected via their hot inlets and outlets. Here's an example from Blender's compositor, where the user holds the Alt whenever they want to insert or detach a node.
In the above example the nodes are connected automatically via their colour coding.
This would especially be useful in live coding/livie noding environments. I wrote a bit about this some years ago https://www.hellocatfood.com/thoughts-on-live-coding-visuals-in-pure-data/