Keep one peice of armor for each slot as your highest Light Level, even if you never equip it. Make sure to have at least one armor of each element for each slot. Related: Destiny 2: How To Reach 1330 Power Level Quickly This system replaced the random-rolled perks on armor in exchange for swappable mods and random armor stats.
The most notable change was the overhaul of armor, otherwise known as Armor 2.0. By looking at the pet's stats, we can see that the maximum strength of the pet is 249, the maximum intellect is 250, the maximum agility is 260, 254 for will, and 250 for strength. scroll down to learn more dm mixedup#3694 on discord to report any issues. That's at least 12 more points to each of those character stats assuming the class item (Warlock Bond, Titan Mark or Hunter Cloak) also gets.
The only vaguely consistent sources are raids, Iron Banner and Reckoning, though even playing all of those this.