Could not passthrough COM port to WSL using STDIO

I have succeeded with COM port passthrough to WSL using TCP. For this I run on WSL
```
socat TCP-LISTEN:1234,reuseaddr pty,link=pty
```
then on Windows run
```
winsocat sp:COM<n> TCP:127.0.0.1:1234
```

I would like to simplify this to one command using `STDIO`.

But if I run from Windows
```
winsocat sp:COM<n> WSL:"socat STDIO pty,link=pty"
```
file `pty` is not created.