Hi,
when I install kicad 6.0.5 under windows, I get a pip.exe in the directory C:\Program Files\KiCad\6.0\bin\Scripts
If I then install kicad 6.0.6 over the previous install, pip.exe is deleted from the scripts directory.
And obviously pip does not work anymore in the kicad command prompt
If I keep a copy of the files pip.exe pip3.9.exe pip3.10.exe pip3.exe from the 6.0.5 installation. And then put them back in the Scripts directory after the 6.0.6 installation. Then pip seems to work fine, and my plugin also works.
I had a similar issue that I discovered when trying to re-install the kikit python packages after upgrading from 6.0.5 to 6.0.6. Using your command to reinstall pip fixed my issue. I think there was a packaging problem for Windows. Is this something to report a bug to using the KiCad Help/Report bug, or do I need to try to find a windows packaging gitlab repository to report the bug there?
(BTW, I experienced this on both Win10 and Win11 computers.)