I currently think that the issue is related to the uWSGI config or some backend dependency since the thing also fails when doing it "locally".
Using the devcontainer in VSCode, I could reproduce the issue.
To get into the devcontainer, simply open the project in VSCode and use Remote-Containers: Open Folder in Container....
Inside the devcontainer you can select the desired version of node. I usually used this command: nvm install Gallium. This will select the LTS version.
Inside src/frontend you can install and build the frontend by calling yarn and yarn build respectively. The last one will automatically create a new folder public in src/backend.
Then in the frontend you'll need to install poetry. The easiest way is simply calling pipx install poetry.
After that the python dependencies can be install by calling poetry install.
If you want to do any changes to the used dependencies, the current versions are stored inside of pyproject.toml.
After having install the python dependencies, the uWSGI server can be started with ./run-web.sh.
The config for the uWSGI servers are in uwsgi.ini.