Swift 6, 76 69 bytes

let f={($0+"").replacing(/one|t[wh]|.i|[fsz]/){" "+$0.0}.dropFirst()} 

Swift 6, 76 69 51 bytes

{($0+"").replacing(/one|t[wh]|.i|[fsz]/){" "+$0.0}} 

Try it on SwiftFiddle!

The output includes an extra leading space.

Swift 5.9, 76 bytes

let f={($0+"").replacing(#/one|t[wh]|.i|[fsz]/#){" "+$0.output}.dropFirst()} 

Swift 6, 76 69 bytes

let f={($0+"").replacing(/one|t[wh]|.i|[fsz]/){" "+$0.0}.dropFirst()}