I don't see you specifically mention it has to be an RPG, so I'll throw in my lot:

Deep Rock Galactic.

-100% cooperative, no pvp.

-Resources found aren't split up, everyone gets the loot.

-Difficulty modes for all level of gamers.

-Randomly generated maps. The same mission can be completely different based on biome, length, complexity, modifiers, and events. Your directional skills will be tested.

-Supportive community. One of the friendliest bunch out there if you play coop.

-If you choose to play alone, Bosco accompanies you, and can accomplish things a solo dwarf would have trouble with.

-4 classes, nice weapon and build variety. Customize for raw damage output, accuracy, AoE, or ammo efficiency.

-Not an expensive game, and DLC is all 100% cosmetic.

-Great music.