Would you consider adding two templates with axis lines, tickmarks, and white background (similar to "xticks" in seaborn)? I believe this is a rather common style in various plotting libraries that also looks good in print and it would be nice to have it easily accessible, especially when teaching so that custom templates need not to be explained early on.

To illustrate what I mean

And with gridlines

I also changed the color rotations to D3, viridis, and RdBu, which are common defaults elsewhere. Below is the code I used to create the first figure, it is not complete with the figure specific template properties that are in the other default templates but gives an idea of what I am referring to.

go.layout.Template(
    layout=go.Layout(
        hovermode='closest',
        hoverlabel_align='left',
        plot_bgcolor='white',
        paper_bgcolor='white',
        font_size=13,
        xaxis=dict(showline=True, ticks='outside', showgrid=False,
                   linewidth=1.5, zeroline=False),
        yaxis=dict(showline=True, ticks='outside', showgrid=False,
                   linewidth=1.5, zeroline=False),
        colorway=px.colors.qualitative.D3,
        colorscale=dict(sequential=px.colors.sequential.Viridis,
                        diverging=px.colors.diverging.RdBu), 
    )
)