OBS Doesnt Detect New Client

Have you tried using the legacy client?

There is a link in the bottom right of the login screen.

I got it to work on the alpha client.

I bet you set it up to look for a specific window name and the new client uses a different game. A monitor capture would work, or you could try remaking the window capture. If you've got a plugin to automatically swap for you it might need to update.