Using Widgets(Button) to initiate Server-Function

Hey there,
Even after a lot of try-and-error i cant figure out to solve my problem:

Whats is the correct/best method to initiate any Gameplay-Logic (basically calling a function on the Server with Authority) from within a Widget on the Client (for Multiplayer)?

Context: I am using the Lyra Starter Project (UE5.1), created a Widget and added a simple Button.
Then in "OnButtonBaseClicked " inside of my Widget, i want to initiate my Gameplay-Logic, which essentially is just Spawning and Equipping a different Weapon.

My code itself works as expected on the Server (Listen Server) and it gets replicated, but if any Client clicks that Button, basically nothing happens.

I tried a alot of differrent Methods, replicating Events on a Server and so on, but nothing really worked (Maybe i just messed those events up)

GA_EquipWeapon (ShopComponent is only made available on the Server with the LYra Setup, but not even the Text is printed on a client) :