iPod 5th Gen auto selecting 'Manually Manage' Music

I have an old iPod 5th gen upgraded to an SSD card. I've synched it using the finder on my 2024 Mac mini. It was set up to synch the entire music library. I regularly plug it in and sync the iPod to add the new music I've loaded into the "Music" app, and it works as it is supposed to, until: About every few days I plug the iPod into , and see that the "manually manage music, movies, and TV shows" under the "general" tab setting has checked itself. If I uncheck it and recheck the "synch entire library" option under the "music" tab it pops up a window that tells me that in order to do that it will wipe the existing library and load the new library. It's the same library, I have changed nothing. As I have almost 500GB of music, that takes a full day. Is there any way to stop that from happening?

[Re-Titled by Moderator]