Well … I had problems installing an anaconda tensorflow version >=2.2. It would only install versions up to 2.1 in a configuration that was acceptabe to KNIME. But maybe you could provide an Environment Propagation that would work (preferably with miniconda and usage of conda-forge - where unfortunately the latest version of tensorflow forf windows is v1.14.0) 
… and working with this example:
With a tensorflow version 2.1 I get some strange error messages. That would be a thing for a new forum entry maybe.