The error in your PowerShell terminal is because the kubectx command is not installed on your system. kubectx is a separate utility from kubectl and is used to quickly switch between Kubernetes contexts.
Try and install kubectx using chocolatey
choco install kubectx
Make sure you have chocolatey installed as well. Do this using https://chocolatey.org/install
You can mark it 'Accept Answer' and 'Upvote' if this helped you
Regards,
Abiola