F# Type Inference By Interpolation Not Working

Thing.fs

module Thing

type Factory<'T> = unit -> 'T

type Printer () =

    static member FactoryInstance : Factory<'T> = Printer.FactoryFunction

    static member DoPrinting () =
        let factory = Printer.FactoryInstance
        printfn $"Values %s{Printer.FactoryInstance ()} and %d{Printer.FactoryInstance ()}"
        
        ()

    static member FactoryFunction<'T> () : 'T =
        if typeof<'T> = typeof<string> then
            box "String" :?> 'T
        elif typeof<'T> = typeof<int> then
            box 1 :?> 'T
        else
            failwith "Type is not supported"