`make_subplots`: setting `row_heights=[xx,0]` creates a subplot that totally hides the other one

    fig = make_subplots(
        rows=2,
        cols=1,
        vertical_spacing=0.07,
        row_heights=[
            300,
            0 + 0,
        ],
    )

(with the rest of the plotting details) will create a plot that the (1,2) subplot will consume it all.

Converting 0s to 1s helps. It should be trivially easy for Plotly to do that.

Oh yeah. Ofc, we are talking again for the Fig_px "works", but fig is broken - #5 by AIMPED setup - which I of course understand is non-standard.