Update 12.2 lost my library (and previous libraries) but not the files

See Empty/corrupt iTunes library after upgrade/crash and Recover your iTunes library from your iPod or iOS device.

tt2

"So I check on internet and everyone pointed out to the Previous itunes libraries folder. Problem: mine is empty!"

Are you sure you're looking in the right place? Check that you don't have duplicated iTunes folders anywhere. If you've upgraded from 12.1 (or earlier) to 12.2 and/or from 12.2 to 12.2.1 there should definitely be dated copies of the pre-upgrade library files in the Previous iTunes Libraries folder:

"Recovery software" is rarely worth what you pay for it (even if free). There's no substitute for creating and regularly maintaining a full backup of your iTunes library as insurance against scenarios like this, as well as hardware failures, malware infections, etc.

In that case, and assuming that checking for tmp files hasn't helped either, you'll have to recreate your library by importing media.

Worked out yet why it's important to create and maintain a backup of your library?

As previously noted, if you don't have a backup of your iTunes library, and you really don't have any older .itl files in the Previous iTunes Libraries folders or recoverable .tmp files in the iTunes folder, and you can't recover content from one or more iDevices, then you'll need to recreate your library by adding the existing media files/folders, re-downloading content from the iTunes Store, etc.

iDevices can only be synced with one library at a time. Since you have - assuming none of the recovery/restoration methods are applicable - a new/different iTunes library and any sync operations will erase media from your iPad. Some of the methods/tools described in tt2's Recover your iTunes library from your iPod or iOS device user tip may allow you to recover some metadata as part of the process of rebuilding your library.

I'm no iOS expert (wouldn't use an iPhone or iPad even if paid to do so) but I believe that contacts, etc. are handled separately from media. I'm sure others with detailed knowledge of iOS devices can jump in with a definitive answer to your question.

As given, the steps listed in Recover your iTunes library from your iPod or iOS device should make sure that you protect all of your other data that is currently on a device when connecting it to what is essentially a new library. There are some scripts listed near the end that can recover ratings, play counts, and playlists. Other tools can be used to recover any media that might have gone missing. There is also a link to a backup method you can use to avoid getting into this position again.

tt2