Unable to sync certain local files to iPhone

[Magicdog]

Plan

Premium

Device

iPhone 11 Pro

Operating System

iOS 13, Windows 10

My Question or Issue

This is absolutely driving me crazy. I've turned off my firewall, enabled cellular download, but for some reason, I can't get some local files to sync to my playlist on my iPhone, but not for others. I've tried deleting and re-adding the songs but I'm still getting the stupid "song not downloaded" nonsense on my phone. I'm already on the same wifi network, and hooking up my PC to my phone's hotspot doesn't do it either. I have no idea what's going on here.

EDIT: I have unchecked "hide unplayable songs", and it seems the songs are marked as unplayable on my phone, even though these songs are local files which I have purchased. Any suggestions to rectify this would be much appreciated