Sync iPhone with new computer

On my other computer I synced my iPhone to it and I clicked only have it sync to this one computer out of some type of paranoia. And I no longer use that computer and it’s no longer alive. So my phone can only sync to that computer but it’s no longer feasible too. Is there anyway to undo the “only sync to that one computer” function without resetting the phone or losing music or files, mainly the music can’t be transferred off or it’d be through a cloud of some sort, and that’s if a reset undoes that function, this may be to prevent any type of transfer of the phone or files.

I backed music up before I ended that computer, but the music was all integrated into windows software code and didn’t come through into the Linux file manager even without bit locker. I wasn’t exactly sure when or what computer I’d buy. But I wanted more than one kind or brand for working with them, but were use to higher performance off market computers, where you couldn’t necessarily install windows or especially not Mac on them, and who knows performance these just may be locked. For some reason they didn’t like us staring into phones or computer ions and programming things into applications or programs. I bought a computer to develop or work on and now think it was a complete waste of time.