Things are going very well to Epic. Exclusive games like Gears of War, Redfall and the next Halo are adopting their engine (I'm not sure if it tells more about Microsoft incompetence or Unreal's virtues).
One of the issues with triple A game dev is that it's hard. No matter what engine you choose. Unity is hard with your hands tied behind your back but UE is also very difficult to get a technically well done game at 60 FPS if you don't have the experience and ability on your team AND management. Some people have been sold the BS that you if you use UE your technical problems are solved and then 1000 blueprints later you are in hot water as you approach ship.
Redfall has been a complete critical failure and the last mainline Gears of War title is from 2019 (and this is a franchise that’s owned by Microsoft - I’m not sure what you mean by “exclusive”). These aren’t particularly good examples.