How to grab all videos from one group to another (VK)?

Question

Video

There is a task: to transfer all videos from one group to another with a simple Python script. The fact is that you cannot download video to your server, you need to do it bypass, that is, using the video.save method with the link argument.
--> I get a link to a video from YouTube, I stick it into the method, it runs - everything works, the video is added, no problems.
--> I get a link to a video that is already in VK and run it through the method, then it returns the 7th error and writes to check the link to the video, since it is not working (the link is 100% working actually) ...
Probably, VK does not allow duplicating video recordings on its servers in this way. Who knows what can be done about it? Maybe I'm doing something wrong? How to implement it correctly?