Divinity: Original Sin 2. Turn-based fantasy RPG that is visually appealing and has interesting writing and a fun, challenging combat system. I've only played solo but it includes local (split-screen) and online co-op / multiplayer. Includes a DM mode for creating custom campaigns which I haven't touched.
Single player consists of choosing an existing character to play, or creating a character from scratch. The typical RPG base classes of rogue, tank, mage, fighter etc. exist but you can mix and match skill trees and equipment to build out characters however you like. You can play as a solo character or party with up to 3 other characters which you'll be able to customize as they level and progress. There is a crafting system, but although I am usually a loot hoarder and avid crafter, I've completely skipped crafting except for a few basic consumables. The crafting might be fun but it's a dimension of the game I just haven't found time or need to explore in my first 100 or so hours of gameplay.
This is the best turn-based combat system I've seen. I've lost my party to poor planning, poor positioning, friendly fire, and challenging AI many times, but every battle seems winnable with the right strategy. Environmental objects can play a huge role, and oil barrels, puddles of water, elevated platforms etc. can make or break an encounter.
Probably my favorite mechanic in the game is the simple Teleport spell. It can be accessed early in game (possibly at character creation) and is the magical equivalent of a Swiss army knife, allowing access to secured areas, loot retrieval, sneaky party positioning or a creative combat weapon.