I had to downgrade Node to LTS version 16.19.0. It then installed npm v8.19.3. Previously I had the latest version of Node 18.x.x
Use guide to downgrade: NVM for Windows – How to Download and Install Node Version Manager in Windows 10
Then when I ran npx create-strapi-app@latest backend --quickstart, it ran successfully and the Strapi admin page loaded in localhost server.