How can I quickly locate and delete object duplicates?

Question

I was handed an older file today to work on, and it features duplicate objects in multiple places which are interfering with the appearance of the renders. I've been able to locate some of those duplicates by manually searching through the 1,000+ objects in the scene, but I'm realizing that this is both slow and inefficient, and so I'm hoping that there's a quicker way to do this. To further complicate the issue that I'm having at this moment, some of the objects with duplicates are set up as reference objects, and so when I think I've found a duplicate, it turns out to be a reference and not the duplicate.

The file is much too large to share, and so if this needs further explanation/clarification, please let me know.

EDIT 1: I'm realizing now that I should mention this: I'm not having success with finding duplicates by just clicking on an object that I think might have duplicates, hiding/deleting them, and so forth until the duplicates are gone. If it were that simple, I would not be asking.

EDIT 2: It occurred to me that seeing the outliner structure might be helpful, so an image is included below now that hopefully does a better job of illustrating at least a part of the issue--basically, if I try to hide or delete one of those copies, it eliminates all of them from the scene.

Answer 1

Here is my scripted solution. Some important deficiencies

1. you don't get to choose which Collection the object remains linked
2. It will remove all multi-collection links for all objects

the script, simplified from @Gorgious comments below:

import bpy

for o in bpy.data.objects:
    # skip non-mesh objects
    if o.type != 'MESH':
        continue
    firstCollectionFound = False
    for c in o.users_collection[:]:
        if firstCollectionFound: 
                print( 'unlinking obj', o, 'from collection', c )
                c.objects.unlink(o)
        else:
            print( 'obj', o, 'in collection', c )
            firstCollectionFound = True

You can try it out:

console output:

obj <bpy_struct, Object("Cube") at 0x000001B627058F08> in collection <bpy_struct, Collection("Collection") at 0x000001B616324E88>
unlinking obj <bpy_struct, Object("Cube") at 0x000001B627058F08> from collection <bpy_struct, Collection("Collection 2") at 0x000001B629E03B88>
obj <bpy_struct, Object("Sphere") at 0x000001B629BFF908> in collection <bpy_struct, Collection("Collection") at 0x000001B616324E88>
unlinking obj <bpy_struct, Object("Sphere") at 0x000001B629BFF908> from collection <bpy_struct, Collection("Collection 2") at 0x000001B629E03B88>