Old macbook pro iTune playlist transfer to Music app on a new mac

I tried to transfer my playlists from my old 2012 macbook pro (running on Mojave) iTune app to a new mac running on Monterey. I did the export library.xml file from the old machine, then import playlist on the new mac. But it says some of the songs are not imported because they are unavailable. So it seems that it imported only the titles of the playlists but not the actual songs. So now I see only a bunch of empty playlists... how do I get the songs in? Thanks!

Also, all these playlists were on my iPhone for years. I just noticed that after many times of iPhone upgrades, some of the data got corrupted - e.g., tracks on multiple playlists got cut in half, or missing pieces of content. Very strange.