I made a stamina system to be able to sprint in multiplayer game. all players can sprint and each of them have individual stamina and if one of them uses all the stamina they cant sprint but other can still do it. the problem is that the widget for the stamina bar gets used up in other players screen. if there is a third player, the bar is not even used in any of them. here is a picture of the blueprints. i used 2 custom events like i did for my shooting to see if it works better
Since max move speed is replicated variable, you need to change it only on server to effect happen on all clients. Same goes for stamina regen.
To make it appear on widget for other clients. You would need to make variable rep notify and detect changes on each client to update current values for widget.