Aquaman was one of the handfuls of characters to benefit (and heavily at that) from the New 52 era at DC. Geoff Johns (surprise surprise) did an absolutely phenomenal job of fleshing out the character and making him interesting and an absolute beast. So I’d start there with Vol. 1: The Trench, followed by Vol. 2: The Others, and Vol. 3: Throne of Atlantis. These are all great stories and you can continue with the run after Vol. 4 as well, although I’m not as big a fan of Jeff Parker’s 2-volume run in Vol. 5 & 6, or Cullen Bunn’s Vol. 7. I like Dan Abnett’s writing well enough (Vol. 8), but Johns’ work on the book was the best.
DC Rebirth Aquaman was solid up until Kelly-Sue DeConnick took over, and even she introduced some really cool ideas, but Aquaman feels far more Aquabro than I personally care for you can take it or leave it. As a side note, the Mera miniseries in DC Rebirth is actually quite good!