This answer worked for me: https://stackoverflow.com/a/78619685/6199781

1. Uninstalling node using fnm uninstall <version> (in my case 20)
2. Then run fnm env --use-on-cd | Out-String | Invoke-Expression
3. Then reinstall node fnm install <verson>

The problem I'm having is that I have to do these steps every time I start powershell. I have no clue how to get the settings to stick.