Some songs no longer playable in Music on my PC but are all available on my iPhone

Thanks for your speedy reply. I did a bit of forensic research into my Library and found that all songs purchased some years ago (2007 through I'm not sure) were no longer playing, even though the Properties associated with each showed that it had been purchased. Attempting one, I finally got a useful error message stating that I must authorize this machine. This is amusing, since I had been using iTunes and Music on this since 2021, and had successfully shared all the music onto my iPhone in 2022. But I have ample room under Match, and dutifully authorized (again) my PC. Now all those songs (so far as I can tell so far) can be played. The list of devices authorized nonetheless looks no different than when I had checked before. Mystery why I would suddenly be deauthorized (and this before I had deleted some old Win 10 iterations of this same PC showing up in the list), and have to reauthorize, but it appears resolved. Perhaps installing Win 11 on my PC made it appear to be a different device??