In async http requests duration for every single request is not shown correctly

I am testing async http requests using NodeJs 14 and AWS Lambda. So, I am doing 100 asynchronous http GET requests and trying measure duration for every single request. Total duration: 5632.74 ms.

  async makeRequests() {
    const axList = []

    for (const item of this.targets) {
        const {url, method} = item
        const config = {url, method}

        const stat = {
            startTime: this.getTime(),
            duration: 0,
            status: 0,
            response: null
        }

        const ax = axios.create()

        ax.interceptors.request.use((config) => {
            config.headers['startTime'] = this.getTime().toString();

            return config
        })

        ax.interceptors.response.use((response) => {
            const currentTime = this.getTime()
            const startTime = response.config.headers['startTime']
            response.headers['duration'] = (currentTime - startTime).toString()

            return response
        })

        const axItem = ax.request(config)
            .then((resp) => {
                const {status, data} = resp;

                stat.duration = resp.headers['duration']
                stat.response = data
                stat.status = status
            })
            .catch((error) => {
                console.log(error)
            })
            .finally(() => {
                this.reponses.push(stat)
            })

        axList.push(axItem)
    }

    await axios.all(axList)

    return this.reponses
}

In this case All requests are asynchronous but duration for every request is not correct or unexpected. Response logs:

  {
    "startTime": 1634169624637,
    "duration": "4063",
    "status": 200,
    "response": {
        "data": "OK"
    }
  },
  {
    "startTime": 1634169624638,
    "duration": "4120",
    "status": 200,
    "response": {
        "data": "OK"
    }
  }, 
  // .... + 97 logs
  {
    "startTime": 1634169624837,
    "duration": "5341",
    "status": 200,
    "response": {
      "data": "OK"
    }
  }

But when I do request synchronously by blocking every request using await inside the loop. I get real duration time for every request.

    async makeRequests() {
        for (const item of this.targets) {
            const {url, method} = item
            const config = {url, method}

            const stat = {
                startTime: this.getTime(),
                duration: 0,
                status: 0,
                response: null
            }

            const ax = axios.create()

            ax.interceptors.request.use((config) => {
                config.headers['startTime'] = this.getTime().toString();

                return config
            })

            ax.interceptors.response.use((response) => {
                const currentTime = this.getTime()
                const startTime = response.config.headers['startTime']
                response.headers['duration'] = (currentTime - startTime).toString()

                return response
            })

            await ax.request(config)
                .then((resp) => {
                    const {status, data} = resp;

                    stat.duration = resp.headers['duration']
                    stat.response = data
                    stat.status = status
                })
                .catch((error) => {
                    console.log(error)
                })
                .finally(() => {
                    this.reponses.push(stat)
                })
        }

        return this.reponses
    }

The duration for every request is realistic now. But it works synchronously which is bad and Total duration much more.

{
    "startTime": 1634162343040,
    "duration": "95",
    "status": 200,
    "response": {
        "data": "OK"
    }
},
{
    "startTime": 1634162343135,
    "duration": "44",
    "status": 200,
    "response": {
        "data": "OK"
    }
},
// .... + 97 logs
{
    "startTime": 1634162349596,
    "duration": "83",
    "status": 200,
    "response": {
        "data": "OK"
    }
}

What can I do for getting correct duration time for every request but at the same time it should be asynchronously ?