The client has appeared on the European PS Store servers too. It would seem, then, that Windjammers 2 — currently announced for Nintendo Switch, PC, and Stadia — is indeed coming to PS4, with an open beta going live in the near future.
PSN releases is an automated Twitter bot account that tweets whenever something new arrives on the PlayStation Store servers. This includes upcoming games as well as patches, so it posts pretty frequently. As you can see below (and pointed out by Gematsu), the account has found a Windjammers 2 open beta:
The sequel introduces an updated art style, new gameplay mechanics and features, and new characters and stages. The action looks to be largely the same, but original moves and abilities look to set it apart from the Neo Geo classic. It was delayed into 2021, but perhaps this news means it’s not too far away now.
Do you want to play Windjammers 2 on PS4? Curve that disc in the comments section below.