iTunes- merge two libraries
I have an older iMac with my whole iTunes library on it (imported songs from CD's, purchased from iTunes, playlists, etc.).
I have since purchased a new iMac and have created a couple video slideshows with music (referencing my bare bones iTunes library on my new iMac.)
I want to bring over my old library onto my new iMac merging it into my bare bones iTunes library on my new iMac. I don't want to just overwrite my library since I don't want my videos to have errors where it can't find the music I have referenced in my videos.
Is there any way to do this without having two libraries on my new iMac? FYI: My old Mac is on a much older OS (10.13.6 since I am still transferring my Aperture photos over to my new computer). I need to update my new iMac as I am currently on 10.15.7.
iMac Line (2012 and Later)