How to plot spheres in 3d?

I am struggling with plotting something, that I thought should be really simple. I have a dataframe/table df that contains the coordinates x,y,z of spheres. Additionally, in a separate column, it contains the radius of these spheres. How can I make with plotly a 3d plot of the spheres in space with their correct radius being used?

The closest I have come to making this plot is this code:

import as px
import plotly.graph_objects as go

x =y=z = np.arange(1,4)

fig = go.Figure()
        marker=dict(color=px.colors.qualitative.D3,size=[50, 5, 25],sizemode='diameter'

This produces almost what I want (see below), but notice that the sizes of the spheres are not correct - the ratios between the sphere sizes are correct, but I want size to provide the absolute size of the spheres in the plot. How can I make this plot work with plotly (or worst case with another library)? Also, I would like to have the spheres being semi-transparent, because some smaller ones might be inside bigger ones and I want to see that. Tnx!

Screenshot from 2022-02-03 19-09-11