Yes, achieving satisfactory NPR results with Unreal Engine indeed poses a lot of challenges due to its structure and rendering pipeline.
In this video, Jumpeter breaks down the most common method for creating toon-looking renders in Unreal Engine 5, outlining its shortcomings. Following this, he offers a new cel-shading approach that doesn't break the physically-based rules of the engine, accompanied by a few tricks to improve the image and re-purposing elements as the outlines to work better with this new concept.
This tutorial's final result can be downloaded on the artist's Gumroad page. You can get the Outlines Filter by clicking this link.
