According to this link, you should append "fetch_status": false in "properties":

          "properties": {
            "display_stash_count": true,
            "display_status": true,
            "display_upstream_icon": true,
            "fetch_status": false            // add this
          },

Restart your terminal and you can see the status icons disappear, and the performance is improved.

Before: https://i.sstatic.net/TpOs3S0J.png

After: https://i.sstatic.net/gzndKiIz.png