Deck spacing is pretty important for getting the most of deck life from you wood.
You’ll find that 1/4-inch is usually adequate for drainage and gunk resistance, though composite deck boards need a little more since they expand and contract with changes in temperature.
You can certainly reinstall your boards with 1/2-inch spacing, but it won’t look quite as nice as it should.
Also, since you’re rebuilding, consider doubling up joists in places where deck board joints will occur.
Leaving 1/2-inch of space between each new joist and its neighbour allows you to space the ends of deck boards for ventilation.
Eliminating end-to-end board contact extends deck life more than any other design feature.