Warframe, One player, two characters (Multi-cam, Multi-boxing, T2 Capture) - YouTube
PS4 version of Warframe needs a performance mode. Or other players should be locked from force starting the mission until all platforms have finished loading out. If they don't want to wait.
Warframe Coop Is Insanely Fun (Gameplay) - YouTube
Is Warframe Crossplay Or Cross Platform? [2023 Guide] - Player Counter