Is key values in a JSON doc indexed?

The source volume is 2.46 TB

ands once its index the store size is 1.1 TB (1 set primary shards and 1 replica)

My Mapping is

"mappings" : {
      "doc" : {
        "_size" : {
          "enabled" : true
        },
        "properties" : {
          "@timestamp" : {
            "type" : "date"
          },
          "@version" : {
            "type" : "text",
            "fields" : {
              "keyword" : {
                "type" : "keyword",
                "ignore_above" : 256
              }
            }
          },
          "hostname" : {
            "type" : "text",
            "analyzer" : "pattern"
          },
          "log" : {
            "properties" : {
              "flags" : {
                "type" : "text",
                "fields" : {
                  "keyword" : {
                    "type" : "keyword",
                    "ignore_above" : 256
                  }
                }
              }
            }
          },
          "log_level" : {
            "type" : "text",
            "analyzer" : "pattern"
          },
          "message" : {
            "type" : "text",
            "analyzer" : "pattern"
          },
          "package" : {
            "type" : "text",
            "analyzer" : "pattern"
          },
          "source" : {
            "type" : "text",
            "analyzer" : "pattern"
          },
          "tags" : {
            "type" : "text",
            "analyzer" : "pattern"
          },
          "thread" : {
            "type" : "text",
            "analyzer" : "pattern"
          }
        }
      }
    }

and I dont know but I didnt see any change in space after force merge, may i did something wrong. I thought of taking up next. But for the sake of completion I am pasting the output here
I had run

POST /index_name/_forcemerge

It ran and provided an output as

{
  "_shards" : {
    "total" : 32,
    "successful" : 32,
    "failed" : 0
  }
}
green  open   index_name              APP-cEzLR-i4vrhoFyL20Q  16   1 6797306863            0      1.1tb        605.2gb

The output for GET /_cat/nodes?v is

10.240.0.26             5          98   9    0.01    0.09     0.08 i         -      coord4
10.240.0.132           48          98  30    2.10    2.19     2.42 mdi       -      node3
10.240.0.27             6          98   4    0.05    0.11     0.09 i         -      coord3
10.240.0.29             4          98  12    0.46    0.45     0.36 i         -      coord2
10.240.0.134           63          98  29    2.71    2.68     2.64 di        -      node5
10.240.0.28            11          98  23    0.57    0.40     0.36 i         -      coord1
10.240.0.12            21          98  25    1.71    2.11     2.25 mdi       *      node2
10.240.0.136           44          98  25    2.84    2.59     2.58 di        -      node7
10.240.0.135           34          96  28    3.21    2.81     2.73 di        -      node6
10.240.0.133           40          98  26    2.62    2.60     2.68 di        -      node4
10.240.0.11            72          97  34    2.72    2.48     2.39 mdi       -      node1
10.240.0.30             5          98  18    0.01    0.05     0.05 mi        -      master

The output for GET /_cat/indices?v

green  open   index_name             APP-cEzLR-i4vrhoFyL20Q  16   1 6797306863            0      1.1tb        605.2gb

The output of GET /_cat/shards?v is

index_name              14    p      STARTED 424166345  37.8gb 10.240.0.133 node4
index_name              14    r      STARTED 424166414  37.7gb 10.240.0.135 node6
index_name              4     p      STARTED 424171600  37.8gb 10.240.0.132 node3
index_name              4     r      STARTED 424171083  37.7gb 10.240.0.136 node7
index_name              12    p      STARTED 424184503  37.7gb 10.240.0.136 node7
index_name              12    r      STARTED 424184511  37.7gb 10.240.0.11  node1
index_name              8     r      STARTED 424192628  37.7gb 10.240.0.133 node4
index_name              8     p      STARTED 424192671  37.9gb 10.240.0.135 node6
index_name              13    r      STARTED 424165421  37.7gb 10.240.0.132 node3
index_name              13    p      STARTED 424164957  37.8gb 10.240.0.11  node1
index_name              10    r      STARTED 424182004  37.7gb 10.240.0.132 node3
index_name              10    p      STARTED 424181156  37.8gb 10.240.0.12  node2
index_name              5     p      STARTED 424184124  37.7gb 10.240.0.136 node7
index_name              5     r      STARTED 424184124  37.6gb 10.240.0.11  node1
index_name              2     p      STARTED 424158150  37.5gb 10.240.0.134 node5
index_name              2     r      STARTED 424157772  37.4gb 10.240.0.132 node3
index_name              6     r      STARTED 424162765  37.6gb 10.240.0.134 node5
index_name              6     p      STARTED 424161952  37.7gb 10.240.0.11  node1
index_name              1     p      STARTED 424148057  37.9gb 10.240.0.135 node6
index_name              1     r      STARTED 424148503  37.8gb 10.240.0.12  node2
index_name              7     p      STARTED 424234489  37.9gb 10.240.0.133 node4
index_name              7     r      STARTED 424233599    39gb 10.240.0.12  node2
index_name              9     r      STARTED 424193478  37.8gb 10.240.0.135 node6
index_name              9     p      STARTED 424193779  37.7gb 10.240.0.134 node5
index_name              15    p      STARTED 424190986  37.6gb 10.240.0.135 node6
index_name              15    r      STARTED 424191265  37.6gb 10.240.0.134 node5
index_name              3     r      STARTED 424224518  37.7gb 10.240.0.133 node4
index_name              3     p      STARTED 424223699  37.8gb 10.240.0.12  node2
index_name              11    p      STARTED 424207929  37.7gb 10.240.0.132 node3
index_name              11    r      STARTED 424207417  37.7gb 10.240.0.136 node7
index_name              0     p      STARTED 424158289  37.7gb 10.240.0.133 node4
index_name              0     r      STARTED 424158641  37.7gb 10.240.0.134 node5

I do have few other indices as well but this is the one that is of major concern