How to sync iPhone without iTunes on iMac late model

I'm on an iMac late 2015 model. My iOS is 12.7.3. I cannot go any higher due to software and hardware mismatch.

In my Applications folder there is NO iTunes app (!) I sync my iPhone using a simple folder. I simply create an "untitled folder" on the desktop. I open it up and if there is no side panel of Favorites and Locations visible (to me they get in the way when I'm placing files on the iMac, so I often turn the side panels off), I can "bring" it back with cmd-opt 's'

Once the sidebar is visible, with my iPhone plugged into a USB port, I can select it in the folder I opened and see the information on my iPhone in this order: "Genera"l "Music" "Movies" "TV Shows" "Podcasts" "Audiobooks" "Books" "Photos" "Files" & "Info"

To get Music on/off my iPhone, I select Music and can adjust what I put on my iPhone - NOTE: I Have 3,225 songs, 106 videos, 1,158Photos and 499 Applications on my iPhone (1TB space) with 766GB left. The categories do NOT necessarily track: I have some videos in the Music portion and some movies under the Movies section. I have some Audiobooks in the Music section, not the Audiobooks section.

I organized my iPhone with playlists. I have 88 playlists that I created in the Music app on my iMac. Now I could have organized the music by "Artists" "Albums" "Genres" or "Playlists". I find Playlists are more sensible and make finding a song easier than knowing the Artist, or Genre, etc. But most any method should work.

Anyway: I select Selected Playlists that I set up in the Music app. I have a folder on my iMac that contains over 921 GB of songs. I can't let the system just add to fill free space, I'll run out!

I add Movies & TV Shows in the TV app.

I add Audiobooks and books in the Book App

I add Photos in the Photo app (Which has other issues!)

I have 24 apps with associated Files

And I use the Info tab to update contacts and Calendars

There is no iTunes that I can even find for my Mac and none for my MacBook pro either!

MY COMPLAINT: The Music app sorts differently on the iMac vs the iPhone. The iMac sorts a music playlist that has a starting numberon the playlist FIRST. The iPhone places that same playlist LAST!

[Re-Titled by Moderator]