The use of animation was a deliberate choice to maintain the anonymity of the protagonist and his family while visually depicting memories for which no live-footage exists. Technical Specifications (Blu-ray 1080p)
The film tells the extraordinary true story of Amin Nawabi, a high school friend of the director, who reveals his hidden past as an Afghan refugee for the first time. Amin fled Kabul as a child, traveling through Russia before eventually finding safety in Denmark. Flee [HD] (2021) Bluray 1080p
You can find the Blu-ray edition at retailers like Amazon or through specialized labels like The Criterion Collection (which released a 4K/Blu-ray combo). The use of animation was a deliberate choice