Quick update on this. i also tested the teardown window incase there was a gap there. registered RplSessionCallbacks, cached the target Room while still in the session, called RequestGameplayEndTransition, then tried RequestConnectViaRoom from EOnDisconnected and EOnEnded plus a 100ms retry loop hammering it the whole way down.

Every single attempt returns false. in session its the invalid state block, and during teardown IsTransitionInProgress() is 1 so it refuses the connect because the end transition already owns the state machine. after that script frames just stop dead, the retry loop never ticks again before Game destroyed.

so theres literally no point in the clients lifecycle where a mod can ask for a connect. session active = blocked, session ending = transition busy, menu = mod scripts arent loaded. its a full catch 22. deffo needs engine support.