graph_objs.volume and .isosurface not rendering non-cuboid

I'm trying to use plotly in a dash app to render a cuboid, that's sheared to the y-axis.=it has a parallelogram as ground surface. It consists of individual points, each with a density value. plotly_express.scatter_3d renders the individual points correctly, but only has "2 views" when rotating it:

• One where the closest face is rendered
• -> you can't look inside very well
• One where both the closest face and the inside of the structure are not rendered
• -> you can only see the 2 rear side faces, but from the inside

With both, I'm losing a lot of information on the insides of my structure.
I think scatter_3d doesn't allow for

• a) all points to stay rendered at all times
• b) me to link each individual points opacity to its density value (like it does with color)¹

Best looking solution would be graph_objs.Volume or .isosurface, but they have an issue.

So far, the coordinates data had to be arranged to form an orthogonal cuboid, to render a volume.
My test data is not the same y-sheared cuboid I want to achieve, but it illustrates the issue of both graph_objs.

Test Data:
Using plotly_express.scatter_3d() for comparison, the following dataframe shows both Figures rendering the expected result:

DF = pd.DataFrame(data={
    'x': [0, 0, 0, 0, 0, 0, 1,1,1,1,1,1],
    'y': [0,0,0,1,1,1,0,0,0,1,1,1],
    'z': [0,1,2,0,1,2,0,1,2,0,1,2],
    'val': [1,1,1,1,1,1,1,1,1,1,1,1]})

scatter plot:

volume plot:

When removing 2 points at (0/1/2) & (1/1/2) -

DF = pd.DataFrame(data={
    'x': [0, 0, 0, 0, 0, 1,1,1,1,1],
    'y': [0,0,0,1,1,0,0,0,1,1],
    'z': [0,1,2,0,1,0,1,2,0,1],
    'val': [1,1,1,1,1,1,1,1,1,1]})

• go.Volume breaks.

scatter plot:

volume plot:

scatter_3d figure:

px.scatter_3d(
    DF,
    x='x',
    y='y',
    z='z',
    color='val',
    opacity=0.5,
    color_continuous_scale=px.colors.sequential.Inferno_r,
    range_color=[df.min()['val'], df.max()['val']],
    template=templ)

opacity doesn't take lists/ranges, so I can't use DF.val there.

Volume figure:

go.Figure(data=go.Volume(
    x=DF.x,
    y=DF.y,
    z=DF.z,
    value=DF.val,
    opacity=0.3,
    surface_count=17,
    colorscale=px.colors.sequential.Inferno_r
))

I played around with surface_count, but it doesn't seem to be causing the problem.

My 2 points being:

• go.Volume/.isosurface don't work if angles of !=90° are involved
• px.scatter_3d deserves some more configuration-options, especially opacity-wise

Reproduce the supplied plotly_express.scatter_3d and go.Volume examples, including the complete and missing-point datasets. Start with the go.Volume and go.Isosurface entry points and compare their behavior for sheared coordinates and missing points. Done should establish whether these inputs are supported and resolve or clearly document the observed rendering limitation.