DPlayer streams are often throttled by the host server. Try using a download manager like IDM (Internet Download Manager) to split the download into multiple threads, which significantly increases speed.
VideoProc Converter: A desktop app that can fetch M3U8 streams and merge them into a single MP4. how to download dplayer video
Look for a large file or a link that populates in the list. Right-click that link and select Open in New Tab. DPlayer streams are often throttled by the host server