What game are your trying to get working?
The Tone Rebellion. It's somewhat obscure, but I chose it because it only uses a few basic DirectPlay features.
My current [development brach](https://gitlab.winehq.org/baskanov/wine/-/tree/dplayx?ref_type=heads) allows it to join a session created by native DirectPlay and play the game to completion.
Are you working off the official dplay4 specifications?
Yes.