Spotify wont download local files

Plan

Premium - Family Plan

Country

Australia

Device

Desktop & IPhone 6s

Operating System

Windows 10 & IOS 12.3.1

My Question or Issue

I'm a bit at my wit's end here, so I'll turn to the community and hope someone can figure this out. Warning for a long post. As simply as I can put it, the situation is this:

-I enable Local Files in Settings and check Local Files under My Library. The songs are there and play fine. They play in Offline Mode.

- I add the songs to a playlist. I click 'Download'. I want to download the Local Files so I can listen to them on my Iphone.

-It 'Downloads' instantly - no loading. The icon next to the Playlist title displays a green arrow icon, like it's downloaded. The song itself, however, does not have a green arrow. It has an empty grey arrow.

- Checking on my phone shows the playlist is empty, and the song has definitely not been downloaded. Trying to play the song on my phone (via my laptop on the same wifi) shows 'Song not Downloaded. If you own the song, you can sync it from your computer'.

- I deselect 'Download', and re-select it. The song is immediately greyed out, and 'Waiting' is displayed. It never downloads. Ever. It just sits there, even after hours.

- Checking 'Local Files' under 'My Library' reveals the song has been deleted from Local Files completely. The program no longer recognises it at all. Only closing and re-lanching Spotify resets everything.

- Result: I can't listen to Local Files offline anymore, or even add them to playlists viewable on my Iphone

Some background:

- The files should be legal. Some are from the internet, some should be from old CDs, some from (new) iTunes. None of them are illegal torrents or rips.

- I WAS able to listen to local files offline until about a month and a half ago. My old local files were working until I made the mistake of removing and re-adding them to see if it was a file type issue.

- My family hasn't reported this issue.

- I am a very active user

What I have tried so far:

-Uninstalled and re-installed Spotify more than six times, including deleting cache data and all records it had on my computer (as well as deleting the app several times)

-Switched up installing Spotify from the site and the Windows Store

-Installed QuickTime player

-Checked if I had enough memory (I do)

- Double checked my files were in MP3, and even got new downloads of the ones I was able to just in case

- Disabled my firewall

-Changing where both the a) local files were stored and b) changed where the offline cache is stored

- Removing all my offline devices from spotify (can't seem to re-sync anything anymore either, so I now have *no* offline devices apparently

- Removing myself from the Family Subscription and re-joining, just in case it solved anything

- Obviously shutting down and re-botting my laptop

- Updating when possible

tl;dr Help I just want my local files again