How do I write a macro that dynamically defines a public or private function?

I’m trying to write a couple macros that define either a public or private functions. Here’s an example

defmodule Defs do
  defmacro mydef(name, do: block) do
    quote do
      def unquote(name), do: unquote(block)
    end
  end

  defmacro mydefp(name, do: block) do
    quote do
      defp unquote(name), do: unquote(block)
    end
  end
end

# Example usage
mydefp hello do
 :world 
end 

Since the functions that are being written are exactly the same except for def/defp, I’d like to extract the function writing logic into a common place

defmodule Defs do
  defmacro mydef(name, do: block), do: do_def(name, block, :def)

  defmacro mydefp(name, do: block), do: do_def(name, block, :defp)

  defp do_def(name, block, visibility) do
    #What goes here?
  end
end

Since def is just a macro on Kernel, I rewrote my macros to look like they were writing function calls.

defmodule Defs do
  defmacro mydef(name, do: block) do
    quote do
      Kernel.def(unquote(name), do: unquote(block))
    end
  end

  defmacro mydefp(name, do: block) do
    quote do
      Kernel.defp(unquote(name), do: unquote(block))
    end
  end
end

From there, it seemed that I should be able to use apply/3 to dynamically call def or defp.

defmodule Defs do
  defmacro mydef(name, do: block), do: do_def(name, block, :def)

  defmacro mydefp(name, do: block), do: do_def(name, block, :defp)

  defp do_def(name, block, visibility)
    apply(Kernel, unquote(visibility), [unquote(name), do: unquote(block)])
  end
end

However, when I use this macro in a module:

defmodule Greeter do
  import Defs
  
  mydef hello do
    :world 
  end

I get the following error:

** (CompileError) iex:3: undefined function hello/0
    (stdlib) lists.erl:1354: :lists.mapfoldl/3
    (stdlib) lists.erl:1355: :lists.mapfoldl/3
    (my_app) expanding macro: Defs.mydef/2

Long question short, how do I dynamically call def or defp so I can share the rest of the logic between my macros?