Moving old iTunes library to Mojave?

I recently purchased a new Mac to replace my aging MacBook Air. Rather than transfer all of my files over, I’m starting with a clean install and only taking some items. One very (very) important item I’d like to transfer is my vast iTunes library, which has spanned over sixteen years and three different Macintosh computers. The old Air is running El Capitan 10.11.6 (with iTunes 12.8.2.3) and the new Mac is running Mojave, so the iTunes application on the new machine is still intact. I started by transferring everything in the Music folder on the old Air to an external hard drive. When I opened the Music folder I noticed it contained the following subfolders:

Album Artwork

iTunes Media

iTunes Music

Mobile Applications

Previous iTunes Libraries

iTunes Library.itl and iTunes Library.xml are both in there, as well.

I did not have the library consolidated on the old Air, although I did have the "Keep iTunes Media Folder Organized" checked. It also looks like the iTunes Media folder location is pointing to something in the Previous iTunes Libraries folder. (I vaguely recall updating iTunes during the old Air’s time and having it wipe a lot of the data - I think I pointed it back to an old folder to get some of that data back).

I don’t recall there being any major issues when I moved my files from the previous Mac to the old Air, which would have been in late 2012. (I do remember losing two or three files, but all the data was OK). However, I wasn’t aware until today of the many different folders, since everything in iTunes on the old Air seemed to be working OK. (Aside from losing play counts on some files when I updated it once, which was a minor concern at the time but I’ve gotten over it. That being said, I wouldn’t want to lose them again). I do know there have been issues moving legacy libraries from very old versions of iTunes into the new Apple Music app, and that is mainly what I am looking to avoid.

a) What is the best way to proceed with the import?

b) Should I attempt to consolidate the files on the old Air first? (One potential concern with this is the old Air is dangerously low on hard disk space and I have many, many music files).

c) If I just drag and drop the contents of the iTunes folder to the Music folder on the Mojave Mac, will that work?

I’ve got backups of everything on the old Air with a separate Time Machine drive.

Also, to complicate matters, I’m an Apple Music subscriber, too.

Any input would be appreciated - my iTunes library is one of my most cherished possessions and it would be a bummer to lose all of that data. Thank you!