Is the RETURN statement necessary in a Function?

Ah, the Return keyword.

No, it isn’t necessary. Outside of a v5+ class, the Return keyword basically just emits to Write-Output and exits. It’s “syntax sugar,” and it doesn’t behave the way Return does in any other language. It’s generally to be avoided. Snover regrets it. Its existence encourages programming patterns that, in PowerShell, are incorrect.

Just use Write-Output.