Complete, faithful adaptation of the full manga, including the deeper trauma/recovery content the 2001 version never reached.
Only adapts early manga content, then writes an original ending due to the source material not being finished yet — a known downgrade from the manga's actual arc.
It's a full readaptation of the same manga from the beginning, not a sequel — made specifically to tell the complete story the 2001 version couldn't finish.
No — the 2019 series stands completely on its own and is the version most commonly recommended as the definitive adaptation.