How to fully uninstall Python from Windows?

[snippsat]

6. pip --version: pip 19.2.3 from c:\python38\lib\site-packages\pip (python 3.8)

Okay.

7. Imported modules: pip install gpxpy: OK, but "WARNING: You are using pip version 19.2.3, however version 20.1.1 is available. You should consider upgrading via the 'python -m pip install --upgrade pip' command." → python -m pip install --upgrade pip: "Successfully installed pip-20.1.1"

This is a normal message,just to remind you to upgrade pip.
I guess you have done this?

python -m pip install --upgrade pip

Test pip -V it should now show version 20.1.1.

So is all okay now dos also python -V work?
Example:

C:\python -V
Python 3.8.2

C:\pip -V
pip 20.1.1 from c:\python38\lib\site-packages\pip (python 3.8)