This is too naive. While it may be the case for single player games that use online connection only as a DRM mechanism (Hitman 3, Gran Turismo 7), for some games it's not trivial at all.
For example, The Division 2 servers do not only act as a "coordinator" between players like CS:GO servers, but also run logics for NPCs and environments. The server and the client are too tightly coupled.