How Do I Delete Photo Library From My Mac Without Deleting From iCloud Photos?

In short, I want to delete my photo library from my Mac without deleting anything from iCloud photos.
For a few years I only used my phone for my photos, but had “My Photo Stream” activated on both my phone and my Mac. That means that a lot of junk accumulated on my Mac that I never got around to deleting. A few months ago I enabled iCloud Photos on my phone, but I purposefully kept it disabled on my computer so my iCloud wouldn’t get all the trash on my computer.
I am tired of not being able to see all my photos on my computer, so now I don’t know what to do. I think that maybe the best solution for this would be to delete the whole photo library currently on my computer, since deleting photos one by one would take an eternity (there’s 13,000+). However, I am afraid that as soon as I turn iCloud Photos on on my computer all of my photos in iCloud will also be deleted. And even if I decided to delete the pictures I don’t want one by one, I am afraid that the ones I don’t delete will be duplicated on iCloud. What would you suggest I do? I already tried Apple Support and they couldn’t give me an answer.
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Guillermo Castillón