a few major flaw lines in the series

really good books and i am buying the all but a major flaw in the plot line never explained.

spoiler dont read one if you dont want.

the golden have a weapon the size of your hand that can make a star supernova and the unseen and golden used them in the previous war with thousands of stars etc. So they cannot be that hard to make..

there are not above sacrificing themselves or ships if need be..

so why when the fleet attacks a system don’t they just sacrifice one ship and turn the star supernova and destroy the whole fleet in on fel swoop?