Hey there diplooo,
Thanks for reaching out to Apple Support Communities. We understand you're wanting some assistance with queuing songs in the Music app on your Mac and would be happy to help assist. Based off the screen recording you provided, this is expected behavior. The article states you are able to drag songs to the center of the Music window if they are from an album or your library. The songs you appear to be dragging in the screen recording are from playlists.
You can queue up the playlist by selecting the three dots next to the "Add" option and clicking "Play Next", but that will begin to play all the songs in that playlist in order. If you are wanting to use the drag method to queue songs, you will need to add those songs to your library first, or you can select the three dots to the right of the song and select "Play Next" or right click on the song you want to add to your queue.
We hope this helps.