iTunes playlist "backdated" when I import it on different Mac

I have a massive 95,000 track 'history of music' playlist that I have carefully constructed over years, and I want to protect the very valuable playlist file and folder of MP3s that are the result of so much work. I frequently export the playlist file and keep it in the iTunes folder.

I am using an old 2012 iMac desktop and an iTunes that hasn't been updated in years to built the playlist. The MP3s live on a Samsung solid-state external drive, along with the .xml Playlist file and the .itl Library file in an iTunes folder.

I use my 2016 Mac laptop to copy the entire iTunes folder containing everything from the aforementioned external drive to another drive of the same type. When I do this, the MP3s copy to the drive, but when I open iTunes on that laptop (first selecting the itl file upon pression Option), and after I select the playlist file that I exported from the History of Music playlist, I find that the playlist that opens is several months old, as if I were importing a playlist that is several versions old. The playlist seems to be a 'snapshot' of the way it was in December 2023, rather than May 2024.

I took the computer to the Genius bar here in Toronto, the Apply guy there couldn't really make sense of the issue, and advised me to "not update anything", for the sake of saving what I already have. We know that updating to iMusic could complicate things as that new program can ignore playlists made out of burning CDs to the old iTunes, which my playlist is largely composed of.

One thing I should maybe note is that months ago, I plugged both external drives into a PC for doing a drive-to-drive file copy, which may have resulted in copies of tracks being made (many of my albums in iTunes recently has double the tracks on a given album, (Track 1 followed by Track 1, Track 2 followed by Track 2 etc). But I'm not sure if this has to do with naything.

Can anyone explain why my playlist, when I try to open it on another Mac, seems to be 'frozen in time'?