In general, the Dorohedoro anime is quite true to the manga. It captures the key elements and the unique style of the source material. Some small adjustments might be made for better visual presentation or to fit the animation format, but they don't deviate much from the manga's core.
The Dorohedoro anime ends approximately at a certain point in the manga, but it's not an exact one-to-one match. Some storylines might be slightly different or left out.