The weird-looking Rust isn’t really Rust being weird, it’s the type telling the truth.

   Result<Option<Result<Message, WsError>>, Elapsed>

That’s three independent “not the happy path” channels: timeout, stream closed, and websocket error.

The nicer version is not a cleverer match. It’s choosing a domain error shape and converting into it one layer at a time:

    let timed = tokio::time::timeout(duration, receiver.next()).await;
    let next = timed.map_err(|_| ReceiveError::Timeout)?;
    let item = next.ok_or(ReceiveError::Closed)?;
    let msg = item.map_err(ReceiveError::WebSocket)?; 

The ugly line is what happens when you have not decided where to normalize the shape yet.