Why are my iTunes songs grayed out on my iPhone?

I use iTunes to create playlists and have several. I worked on these over time for years. I began syncing my iPhone (15 Pro Max) and soon discovered that, not only were many songs not brought over to my phone, but it was actually also removing songs from my playlists on iTunes. Infuriating. So, after working on getting those back up, I no longer use sync. I am now manually adding songs into newly created playlists on my phone that match iTunes.

Now, I'm seeing that, in some cases, nearly an entire playlist is grayed out and will not play. The songs are also not showing on my phone. In many cases, these are songs I actually purchased from the iTunes store. Also, a huge number of songs that were ripped from CDs are not showing.

I DO NOT subscribe or have Apple Music. I do not want it. This was never a problem before its inception. I understand the "matching" thing, but I am not an Apple Music customer, so why in the world would it not recognize song files that are on the phone? These files exist and should be able to be played.

Apologies if this is an issue that has already been addressed, but every "solution" I have found mentions Apple Music and to ensure I'm subscribed and signed-in. No and no, because I don't want it or need it.

Also, I do not use the iCloud, but am open to the possibility some settings are conflicting. BUT, again, no thread I've been able to find here or elsewhere seems to talk about my exact problem.

I will add that I am using a very old HP desktop PC currently for iTunes. Still have Windows 10. I have a hard time believing this is the issue since it has never been before, but what do I know? I just want the songs that I OWN to play on my device.

Thanks to anyone who can provide any assistance.

[Re-Titled by Moderator]