Create a new variable on the BP_MasterRangeWeapon bp, its type should be Vector and it should be called Screen Center.
Then add it to the Screen Trace function shown below
In the BP_SurvivalInventoryInterface go to the Left Mouse Input Action and add a new input type Transform and call it Screen Center. Like shown below
After adding that you may have some errored nodes in your bps, so you need to go to the BP_MasterHoldable and compile it. Then to the BP_MasterInventoryComponent and compile that as well. If you still have errored nodes in any bps just recompile the bp that the error is in and it should fix it.
Next copy the image below
Next in the BP_PlayerInventoryComponent find the Server Left Mouse Input Action event select it and add a new input type vector called Screen Center. Like the image below
Then select the Left Mouse Action Input collapsed nodes next to that node and add a new input the same as the events one you just created and connect them up like shown below.
Next in the collapsed nodes connect the vector input to the 2 nodes shown in this image
Next create the highlighted nodes and connect them to the nodes shown, like in this image below. I have moved left mouse nodes to make it easier to see.