I found this glitch, all you have to do is lock yourself into place and drop all your decoys on yourself and when you start getting shot, spam L1 to keep adding decoys on yourself. Every time a decoy dies you get one back so the strategy is infinite as long as you never stop pressing L1 as fast as you can.
Call of Duty®: Black Ops 4
https://store.playstation.com/#!/en-us/tid=CUSA11100_00