Syncing existing iPhone to an iTunes library on a new windows computer.

I recently replaced an old Windows 11 computer with a new Windows 11 computer. I did a fresh install of iTunes and then created a new iTunes library on the new computer from all of the music files I moved from the old computer. I also imported all of my Playlists that were on the old computer. Everything is hunky dory on the PC!

I have an iPhone that has all of the music from the old computer's library and am trying to sync it to the new iTunes Library on the new computer. When I try to do so I get a message saying that I don't have enough space on my iPhone. Apparently, Windows iTunes isn't recognizing that the iPhone already has all of the music (except for two new songs) and is only looking at the free space on the device. I am guessing that I need to delete the existing music and the library on the iPhone that was created from the old computer and start all over again. What is the easiest way to go about this?

Thanks in advance, and don't hesitate to point me to any documentation on this.