My Lightroom Catalog is too big.

I am a photographer with years of photos in my computer.  I have over 380,000 photos and my LR catalog is 4.2 GB.

I use an iMAC with plenty of internal memory (32GB) and have plenty of storage.  I am running Lightroom Classic CC - current version.  I did get the warning message about the Library size and lately there has been a noticeable slowdown in LR.  This happens particularly when I change modules - Library to develop or when I use the Crop tool.  I understand the problem, so I have multiple questions:

1.  Is there ANY way to split a Library?  My photos are in folders by the year taken and I would love to take just 2017 and 2018 and start a new Library.

2.  If #1 is not possible, I will create a second Library and add photos to it.  I did a test, however and imported a few hundred photos into the new Library.  Unfortunately, all of my extensive keyword work does not come with the photos.  Does anyone have a suggestion how I can maintain the keywords, ratings and color labels that I have on my photos?

Thanks in advance to anyone with suggestions.  I'm sure I am not the only one with this problem.
--Tom L

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