I didn’t find a solution that simple changes which traces are in the front and which are in the back. But there might be another option - by setting a constraintrange on the go.Parcoords, you can limit which lines are initially displayed.
It’s a solution but it’s not different from just doing it manually in the html file.
my need is really to have the lines going to lower values that are in the foreground.
an idea was to use fig.update_traces(line_reversescale=True)
but it just reverses the colours. So a similar but working idea would be to literally reverse the axis (display the lower values in the top) the problem is that I do not know a method to do it.