This is absolutely impossible. First of all, pro 2. 1 does not support mp4 format, so you need to cut music from video format. Second, the reason why edit can eliminate the voice of the singing part of the song is because the music has two channels, and the human voice is only recorded in one channel, so the software deletes one channel, leaving only the music channel, and copying the music channel to the other channel forms the accompaniment. Your music has exactly the same two channels. So no.

I suggest you download the piano solo mp3 format of this song directly from the Internet, and then insert the recording.