No model for FigureWidget

Despite following the troubleshooting instructions at Troubleshooting | Python | Plotly, uninstalling with

$ jupyter labextension uninstall jupyterlab-plotly
$ jupyter labextension uninstall plotlywidget

ī‚± jupyter labextension list                                                                                                                             30.3s ī‚³ Fri Feb 19 07:08:12 2021
JupyterLab v3.0.7
/usr/local/share/jupyter/labextensions
        jupyter-matplotlib v0.8.3 enabled OK
        @jupyter-widgets/jupyterlab-manager v3.0.0 enabled OK (python, jupyterlab_widgets)

Other labextensions (built into JupyterLab)
   app dir: /usr/local/share/jupyter/lab


Uninstalled core extensions:
    jupyterlab-execute-time
    plotlywidget

then reinstalling with

jupyter labextension install jupyterlab-plotly@4.14.3                                                                                                1891ms ī‚³ Fri Feb 19 07:08:34 2021
Building jupyterlab assets (production, minimized)
 ~/D/w/pvpython ī‚° ļ˜ ļ‘ˆ ļ„Ø  ī‚° jupyter ī‚°
ī‚± jupyter labextension install @jupyter-widgets/jupyterlab-manager plotlywidget@4.14.3                                                                   1.4m ī‚³ Fri Feb 19 07:11:10 2021
Building jupyterlab assets (production, minimized)
 ~/D/w/pvpython ī‚° ļ˜ ļ‘ˆ ļ„Ø  ī‚° jupyter ī‚°
ī‚± jupyter labextension list                                                                                                                              1.2m ī‚³ Fri Feb 19 07:12:52 2021
JupyterLab v3.0.7
/usr/local/share/jupyter/labextensions
        jupyter-matplotlib v0.8.3 enabled OK
        @jupyter-widgets/jupyterlab-manager v3.0.0 enabled OK (python, jupyterlab_widgets)

Other labextensions (built into JupyterLab)
   app dir: /usr/local/share/jupyter/lab
        jupyterlab-plotly v4.14.3 enabled OK
        plotlywidget v4.14.3 enabled OK


Uninstalled core extensions:
    jupyterlab-execute-time
    plotlywidget

Running jupyter lab and creating a fig = go.Figure() works fine, but attempting to create a FigureWidget with

figgy = go.FigureWidget(fig)
figgy

generates Error displaying widget: model not found.

Looking in the browser console, I see

Error: Module plotlywidget, semver range ^4.14.3 is not registered as a widget module

I have run jlpm cache clean followed by jupyter lab build.

pip list reports

pip list                                                                                                                                              40.3m ī‚³ Fri Feb 19 07:08:23 2021
Package                           Version
--------------------------------- ----------
-upyterlab-server                 1.2.0
anyio                             2.1.0
appdirs                           1.4.4
appnope                           0.1.2
argon2-cffi                       20.1.0
arrow                             0.17.0
asgiref                           3.3.1
async-generator                   1.10
attrs                             20.3.0
autopep8                          1.5.4
Babel                             2.9.0
backcall                          0.2.0
bandit                            1.7.0
binaryornot                       0.4.4
black                             20.8b1
bleach                            3.3.0
certifi                           2020.12.5
cffi                              1.14.4
chardet                           4.0.0
click                             7.1.2
cookiecutter                      1.7.2
cycler                            0.10.0
decorator                         4.4.2
defusedxml                        0.6.0
Django                            3.1.5
django-appconf                    1.0.4
django-crispy-forms               1.10.0
django-passwords                  0.3.12
django-richtextfield              1.6
django-select2                    7.6.1
django-session-security           2.6.6
entrypoints                       0.3
gitdb                             4.0.5
GitPython                         3.1.12
idna                              2.10
ipykernel                         5.4.3
ipympl                            0.6.3
ipython                           7.20.0
ipython-genutils                  0.2.0
ipywidgets                        7.6.3
jedi                              0.18.0
jellyfish                         0.8.2
Jinja2                            2.11.3
jinja2-time                       0.2.0
json5                             0.9.5
jsonschema                        3.2.0
jupyter                           1.0.0
jupyter-client                    6.1.11
jupyter-console                   6.2.0
jupyter-contrib-core              0.3.3
jupyter-core                      4.7.1
jupyter-nbextensions-configurator 0.4.1
jupyter-packaging                 0.7.11
jupyter-server                    1.3.0
jupyterlab                        3.0.7
jupyterlab-pygments               0.1.2
jupyterlab-server                 2.2.0
jupyterlab-widgets                1.0.0
kaleido                           0.1.0
kiwisolver                        1.3.1
Mako                              1.1.3
Markdown                          3.3.3
MarkupSafe                        1.1.1
matplotlib                        3.3.3
mistune                           0.8.4
mypy-extensions                   0.4.3
nbclassic                         0.2.6
nbclient                          0.5.1
nbconvert                         6.0.7
nbformat                          5.1.2
nest-asyncio                      1.5.1
notebook                          6.2.0
numpy                             1.19.5
packaging                         20.9
pandas                            1.2.0
pandocfilters                     1.4.3
parso                             0.8.1
pathspec                          0.8.1
pbr                               5.5.1
pdoc3                             0.9.2
pexpect                           4.8.0
pickleshare                       0.7.5
Pillow                            8.1.0
pip                               21.0.1
plotly                            4.14.3
poyo                              0.5.0
prometheus-client                 0.9.0
prompt-toolkit                    3.0.14
protobuf                          3.14.0
psycopg2                          2.8.6
psycopg2-binary                   2.8.6
ptyprocess                        0.7.0
pybind11                          2.6.2
pycodestyle                       2.6.0
pycparser                         2.20
Pygments                          2.7.4
pyparsing                         2.4.7
PyQt5                             5.15.2
PyQt5-sip                         12.8.1
pyrsistent                        0.17.3
python-dateutil                   2.8.1
python-slugify                    4.0.1
pytz                              2021.1
PyVISA                            1.11.3
PyYAML                            5.3.1
pyzmq                             22.0.2
qtconsole                         5.0.2
QtPy                              1.9.0
regex                             2020.11.13
requests                          2.25.1
retrying                          1.3.3
scipy                             1.6.0
seaborn                           0.11.1
Send2Trash                        1.5.0
setuptools                        53.0.0
six                               1.15.0
smmap                             3.0.4
sniffio                           1.2.0
sorl-thumbnail                    12.7.0
sqlparse                          0.4.1
stevedore                         3.3.0
tbb                               2021.1.1
terminado                         0.9.2
testpath                          0.4.4
text-unidecode                    1.3
toml                              0.10.2
tornado                           6.1
traitlets                         5.0.5
typed-ast                         1.4.2
typing-extensions                 3.7.4.3
urllib3                           1.26.3
wcwidth                           0.2.5
webencodings                      0.5.1
wheel                             0.36.2
widgetsnbextension                3.5.1

Iā€™m running Python 3.9.1 installed with homebrew on a Mac running macOS Big Sur 11.3 Beta.

Any thoughts?