I quite often include a series for percentage in my charts meaning I need to set “Combine Axes” to OFF.
This is fine unless I start adding more measures or table calculations - when I do, I get an extra y-axis for each measure/table calculation.
Whats worse is each y-axis has its own scale. Although I could theoretically control that with y_axis_min & y_axis_max, in practice I don’t know what the numbers are in advance and I can’t use expressions to populate these ranges:-

This stops me from doing various things:-
Adding a table calculation to shade a specific area of the chart (middle 50% etc) - I cant guarantee the scale will be the same, so the shading may not fit the line.
Adding a table calculation to mark when specific events occurred or simulating x-axis reference lines
etc.
Ideally, I would be able specify the number axes, which series are on each axis and also use expressions to set axis min and max (i.e axis_max: max(r_total))