How to play with a friend if he has a Steam version and I have an Epic games version? (Saints Row: The Third)

Saints Row: The Third Remastered

The platform is one with another PC, but we cannot connect for joint play. A playground serves as a stick in the wheels. Only one STEAM has two identical versions of "Remastered", while the other has Epic games.
Yes, there is a binding in Epic games with "steam" this procedure was done, the result: - I see it "steam" acc and send an invitation, but the invitation itself does not come to the game. (if he sent me an invitation from the Steam, then he sends it to the page of the game for purchase.)

Can you please tell me how to proceed and decide?