imo that’s the most important missing feature in UE4 networking. i need it badly too.
i have two workaround for this. one is described here: Best way to replicate timeline-changing anim variable? - Editor Scripting - Unreal Engine Forums
and is BP timeline oriented, being hacky and unrecommended.
the second way is C++ and is adding a 4th version for the function, which in my case i call _startThenSync
you can call _locally from inside of it and then triggering _onServer. (which calls multicast afterwards)
on need you can add more logics for the calling client into that _startThenSync, like for example GUI update (which can be irrelevant to multicast if it’s player-specific GUI).
This way you can also avoid command delays, because you start your action straightaway in offline before the server receives and triggers multicast back. of course you need to apply caution and prevent cheating form happening, so that would be bad for damage/death etc…
If you utilize that wisely, actions won’t happen twice on the calling client (once locally then second time by multicast)