@King_of_Oz I have worked with both engines, there is no single "better" engine.
Unreal's shadow cascading is more advanced while also supporting soft shadows via raytracing.
Unreal also has a more robust materials system. Allowing for more complicated shaders.
Unreal is also more robust when it comes to specific tick rates (tick is the term that's used when referring to the time it takes to initialize an operation). You want to have a certain operation tick every 4 seconds while having another tick 40 times a second? No problem.
Unreal also allows for faster physics calculations (partially thanks to a very customizable tick rate), thus allowing physics to behave properly in "high speed" situations.
Overall better post process effects. Unreal bloom > Unity bloom.
World origin rebiasing allows for single extremely large worlds, or even infinite worlds while still allowing physics to behave normally.
Unreal's source code is open source, meaning that it's easily modifiable.
Now for Unity.
2D specific physics is very nice, and allows for better control of 2D only games (this includes 2.5D).
C# is more forgiving then C++, and has a shallower learning curve. While Unreal's Blueprints tend to mitigate this a bit, i'm still going to give Unity this one since I feel charitable today.
Unity is overall easier to pick up and learn.
Better mobile support.
More assets, which can help speed up the development process. While this can also lead to more untalented "asset flippers" (which is a huge reason for Unity's poor reputation among certain folk) that isn't the purpose of assets, and it's not really Unity's fault that this happens. Hell, this happens in Unreal as well. Although to a lesser degree.
Better support for dynamically lighting sprites, and better sprite support in general.
Unity has more plugins.
Unity can run on lower end hardware out of the box (although tweaking some settings in Unreal can go a long ways). Both use system resources about equally when fully decked out in the graphics department.
NETHER engine is better, while Unity excels at some things, Unreal excels at others.