Step1: Get-ExecutionPolicy for your Machine using the below command
Get-ExecutionPolicy -List
Step2: Once your identity scope and execution policy, please run the below commands using the same.
Set-ExecutionPolicy -ExecutionPolicy RemoteSigned -Scope CurrentUser
if above doesn't work, install the minimum node version angular required and run bellow command
npm install -g @angular/cli
if you want handle multiple node version use nvm as follows;
https://www.freecodecamp.org/news/node-version-manager-nvm-install-guide/