A new season of Destiny 2 usually brings with it a slight downgrade in character power, as the seasonal artifact for the previous three months is retired and replaced with a new one. If you’d maximized your overall power level in Season of the Haunted, then you’ll likely be starting Season of Plunder back at a power level of 1560. As of now, players can start working to the soft cap of 1570 and grind high-level events to reach the hard cap of 1580.
The soft cap, which can quickly be reached by earning new armor and weapons from seasonal and Vanguard activities, will have you reach the 1570 power level quickly and easily enough. As a reminder, that means that each one of your three main weapons and five armor pieces will need equipment rated at 1570 for you to achieve that overall average (unless you exceed that number in certain slots).
Random loot drops and Powerful Engrams will help boost your numbers, but to reach the 1580 hard cap, you’ll need to do some real grinding to earn Pinnacle Engrams. These will help push your Guardian up to 1580–albeit slowly–and can be earned from high-level activities. The following activities will reward you with Pinnacle Engrams that will help you get those last few numbers necessary to reach the hard cap: