SEGMENT MERGING

I recently reindexed where I had to update docs multiple times and deleted huge amount of docs.
I see deleted and updated docs are still occupying disk space. From my research so far, force merge of segments is not a good idea since it could create more segments with huge size and could backfire. What can be the safest way to get rid of those unwanted space? Or should I just leave it alone, and over the time it will go away on its own?

Following is the screenshot of my index that has 1 replica. You can see the highlighted part. It is way more
Capture

It's not clear what those numbers actually represent, and I'm not familiar with the UI you've taken a screenshot of there. Is it possible that the numbers in brackets are the total of primary plus replica, and the numbers outside the brackets are just the primaries? I ask because 5.51TB is about twice 2.79TB, and also because there's no way to measure the size of documents-that-have-not-been-deleted so that can't be what that 2.79TB is reporting.

But yes, as a rule, you should leave merging alone and let Lucene do its thing.

Thank you for your response. UI is Elasticsearch Head. Yes, number inside the bracket is primary+replicas