How can you create renders like these? Are these baked lighting or some kind of custom shader?
It’s done in Unity. miHoYo has built their own shaders in unity while developing Genshin Impact and have been revising it up until ZZZ.
A tutorial how to achieve a similar look in ue
If you want the unreal equivalent for cel shading then look into the "Guilty Gear series and “Granblue Fantasy”. (both in Unreal) and maybe the Street Fighter 5. Perhaps there are some tech presentations that can show the technique in unreal in deeper detail.