Downloads expire after a certain period (often 30–48 hours after starting playback) and cannot be transferred to other devices.
However, I must clarify that is a streaming platform that hosts original web series, often with mature content. “Walkman” is not a confirmed UllU Original title as of my latest knowledge update. It is possible you are referring to a niche or regional release, a fan-made concept, or a confusion with another series like Walkman (maybe a music-based drama) or a mistyped title. Download - Walkman - Part 3 -2022- UllU Origin...