You need to duplicate not just the one composition, duplicate and relink the comp and all the precomps that it relies on.
Two options:
1) True Comp Duplicator does this with just a couple clicks: https://aescripts.com/true-comp-duplicator/
2) Manually, you can isolate the comp and all dependencies that you need, then reimport it multiple times into your project file. File > Save As…, and choose a new filename for your AEP. Select the comp you wish to duplicate, and with that selection choose File > Dependencies > Reduce project. This will remove everything from your project except the comp you selected and the items upon which it depends. Re-open your original AEP, then import the new reduced AEP to get the independent comp/precomp structure. You can re-import as many independent copies as you’d like
Walter Soyka
Designer & Mad Scientist at Keen Live [link]
Motion Graphics, Widescreen Events, Presentation Design, and Consulting
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