I am trying to make a similar figure as yours.
If I understand it correctly, I make the two parts adjacent by setting the domain values. For example, I set the domain of my xaxis1 as “domain”: [0, 0.75] and xaxis2 as “domain”: [0.75, 1] so that the two part get adjacent with each other. I assume the two parts could be separated by a border of by adding a no-value axis, but I’m sorry that I do not really know how to make it.
However, I am quite new in Plotly, so I am not sure whether it is a good way. Hope it could help you…
By the way, I have a question: could you make the borders of the second figure (I mean, the right one) appear? I tried but they kept hidden!..