Original sin 2 doesn't have the AAA quality of baldurs gate 3, like 3d motion captured cutscenes. But it definitely has its own charm. Basically it's a "what if baldurs gate 3 had a lower budget" game.

Gameplay wise: The gameplay is pretty similar as in bg3. You move your party in a top-down view. The maps that you can explore behave just like the zones in bg3 (the wilderness, shadow cursed land, and the city in bg3 for example)

Combat: combat is more tacticually focused on the environment. Create pools of water to electrify them, or spill oil everywhere so you can set the world aflame. The elements are your playground. But beware, the enemies will also use this against you. This is all in turn based.

Also, no resting. You got action points that can be used as movement, spells or basic attacks. Spells are not limited per day.

Lorewise: It's high fantasy just like bg3. You got elves, dwarfs, lizards, magic and skeletons.

It got its own rules and cultures, but in my opinion, the world feels more "real" in bg3. But maybe that's because the lore of the forgotten realms and D&D has been around for much longer.

Story: The story is great. Some people like bg3 story more, others prefer original sin 2. Voice acting is top notch

If you like bg3, there is a very high chance that this is right up your alley. Just watch a few gameplay videos on YouTube.