Deleting duplicates from Lightroom (formerly Lightroom CC)

Help!  I just migrated from Lightroom Classic to Lightroom, and I know I have lots of duplicates (they've accumulated over years of imports in various Adobe products).  I've been putting off cleaning them up, and I thought I'd get it done after I got started in the new (to me) platform.  Now, I'm finding out that cleaning up duplicates in the cloud is a nightmare.  Soooo... a few questions:

- I'd like to use a product like Gemini to clean up my files and then synch only the remaining files.  Is that possible?
- Or, is there a way to "start over" the synching after I clean up the originals?  
- Or, is there a way to de-dup the cloud files?  
- I don't see a way to view the cloud file structure.  Is there a way to do that?

Basically, I'm looking for some way - other than manually reviewing over 100k photos - to de-dup in bulk.

Note, I have years of data - edits, keywords, etc. - that I'd prefer not to lose as I de-dup.

Any ideas?

TIA!!

PS Like so many others, I would LOVE a de-dup feature built into the app!!!

[Moved to Lightroom ecosystem by moderator]