The best and legal way to watch content offline is through the official ViX mobile app (Android or iOS), which allows downloading selected content for offline viewing, similar to YouTube Premium offline.
Use to download the video: ffmpeg -protocol_whitelist "file,http,https,tcp,tls" -i playlist.m3u8 -c copy video.mp4 . Understanding VIX Premium Download VIX PREMIUM [KEPAHOO] txt
Navigate to the video page and use a tool like Video DownloadHelper to find the .m3u8 link. Download the .m3u8 file. The best and legal way to watch content