What is the best way to download 4K videos to an iPad?

Hi, I have a M1 iPad Pro 12.9". I want to not only watching but also downloading the videos in 4K. What is the best way to do it? In the past there were websites which accepted urls and auto converted and saved the videos. However, recently those websites became doggy so I am looking for a safer

Download Videos in 4K on PC, Mac, Android & iPhone

4K Downloader for iPhone and iPad

How to Convert MP4 to iPad for Smooth Playback?

How to Save 4K Video to iPhone in Best Quality

Play 4K, 60FPS Videos, or even Audio from on iOS

Grab Your Favorite Embedded Posts with 4K Video Downloader

How to Download Video To iPad — Every Movie Has a Lesson

Gigastone iPhone Flash Drive w/ a 32GB card, MicroSD Card Reader

5 Best Ways to Download s to iPhone/iPad

How to shoot 4K video at 60 FPS on iPhone and iPad

How to download Music Playlists to iPhone, iPod or iPad

Top UHD Video Player on iPhone / iPad