Ahh Good Job !!
Another thing I just noticed, because this is for 16 players, and it likes to have 1 spawnpad per player, you will need 16 spawnpads for each spawn set.
Put in 16 Pregame Spawnpads and 16 Gameplay Spawnpads.
Your idea of a tracker and item granter for the winner should work.
Tracker set to count rounds won, target value 1.
unless the round ends before the item granter has time to grant from the trackers round winner completion event.
Maybe could set the item granter to grant at the start of the round, based on the tracker completed event, then manually resetting tracker and re assign to all ???.
But if you have Worked out Player Counters and using End Game device to end round, the item granter can be linked to the player counter, grant item on count success, without the need for a tracker.
Another way to give weapons is by a class change, and this lets you change some players stats & abilities as well as items.