I have been trying to get the Python integration to work with Knime.
I followed the instructions, and set up a Py3/Py2 environment using Knime. These appear fine, and without errors.
When I try to run a Python node however I get an error that the path to the python executable is not set. I cannot see an option to set this, other than choosing the conda install location and the environment. Clearly since Knime can see the environments it is looking in the right folder?
I think you are mixing up different Python integrations. The preference page in your screenshot belongs to the KNIME Python Integration – KNIME Hub provided by KNIME (the company).
If you want to use the community extension, you will need to configure Python via Preferences > KNIME > Python Scripting as stated in the error message. If you want to use the extension provided by KNIME, then the node most similar to Python Plot should be this one: Python View – KNIME Hub