FTS Error(s) context deadline exceeded

If you have further mutations/updates happening in the system, then you could try to update your index definition with the below store options to see any difference in index size,

"store": {
      "indexType": "scorch",
      "numSnapshotsToKeep":1,
      "scorchMergePlanOptions": {
          "maxSegmentSize" : 100000
    }
  }

One could use the options like “Show curl command to modify this index definition” and “Copy” on the index listing page to get the current index definition and update it.

The assumption here is that you have the default index partition count of 6 here.