I looked at an example of using relay in netcode for entities(
01_BootstrapAndFrontend, 01b_RelaySupport), but my server is a host with a local client and I get an ipc connection error, I looked at the code and saw comments for some classes there, changed the endpoints of both the client and the server in the SetupRelayHostedServerAndConnect() method in RelayFrontend class to anyIpV4.WithPort( 7979), and also changed the RelayDriverConstructor method RegisterClientDriver() to DefaultDriverBuilder.RegisterClientDriver with relayServerData, and everything seems to work fine, except that the local client apparently still uses the UDP connection and it all works only in the editor, and in the build an InvalidException like relay cannot use with ipc connection