Confused about what I've done and how to fix it!

Hello folks, Firstly apologies for the nativity of my question and if it has been asked & answered before.

Background: I have a Mac Book Air and an iPhone 11, both on up to date IOS. I am an Apple Music subscriber. I have roughly 3,500 tracks in my music library - some of which were uploaded from CDs years ago (which have long since been thrown away!), some were bought in iTunes prior to having my subscription, and some downloaded post subscription.

I never use my Mac to play music or look at my library as I do it all on my phone. However, yesterday I was going through my music library on my Mac and noticed I had hundreds of duplicate tracks. I'm aware there is a 'show duplicate tracks' function, but I took the time to scroll through all my tracks manually and removed what I thought were duplicates. Each time, I got a prompt on the screen saying one of two things:

1) "Move to bin" or "Keep file" or "Cancel"

2) "Delete song" (Yes/no)

When the first prompt popped up, I selected move to bin. This was only for probably about 10% of the duplicates I deleted. When the second prompt popped up, I selected Yes.

The remaining duplicates stayed in my music library on my mac, and I can still see them there now, one day hence. However - it now appears that every 'duplicate' track I deleted has disappeared from the library on my phone. I have tried syncing again and it hasn't reinstated the missing tracks.

I have also tried unchecking sync library on my mac and phone - nothing.

I considered doing a restore, but it appears the last time I backed up my phone was 2019! Stupid, I know, but I'm not generally aware of the need to do this (well, I am now) and I think it's probably because I now do everything via wifi/bluetooth. It has always appeared my two devices were perfectly synced and so the need to plug my phone into my mac and back it up never occurred to me.

I also, stupidly, deleted all the tracks from my trash. So, my question to you fine folk is - how do I undo my stupid mistake?! I don't live near an apple store and just want my tunes back on my phone. I can see them in my mac music library!!

Throwing myself at your mercy.

Thanks so much in advance.