How are you supposed to grind 2000 power levels now?

I left the game shortly after Edge of Fate. Just had no desire to play after the introduction of the portal, tiered loot, and power levels being reverted to near zero.

After nearly a year, I'm getting back into it and having fun. But my power level is at around 300, and the pinnacle cap is 2020. How the hell are you supposed to quickly and efficiently get nearly 2k power levels? After years of increasing my level by increments of 10-20 every season since Shadowkeep, it suddenly all got taken away. And the power grind that players complained about returned in the worst way possible.

I've been absent for so long that I don't really know the current content that well or how to grind efficiently. Any tips?