I have many API endpoints with same base data format. I want to get data from them and unmarshal response to specific struct or format.
For example we have following endpoints and example responses:

GET /api1

{
    "data": [
         {"username": "Marcelo Roberts Sr."}
    ]
}

GET /api2

{
    "list": [
         {"id": "Vernon Effertz"}
    ]
}

Responses in my case is more complex. Anyway I want to convert this responses to one format. For example all of them use following struct:

type Res struct {
    Identifier string `json:"identifier"`
}

I want to convert all of responses to an object from []Res.

I use following code for converting each type:

func getData() (string, error) {
    var response struct {
        Data []struct {
            Identifier    string `json:"username"`
        } `json:"data`
    }
    rawResp, err := http.Get("https://domain/api1")
    if err != nil {
        return "", err
    }

    byteResp, _ := io.ReadAll(rawResp.Body)

    err = json.Unmarshal(byteResp, &response)
    if err != nil {
        return "", err
    }

    var prices = make(map[string]Price)
    for _, obj := range response.Data. {
        prices[obj.Username] = Res{
            Identifier:     obj.Identifier,
        }
    }

    stsandardResponse, _ := json.Marshal(prices)
    return string(stsandardResponse), nil
}

I have lots of endpoints like this. How can I simplify them and avoiding DRY ?
I know this functions just have different on 3 section. a) Label of nested struct b) Path of final struct Res like data c) Where we should iterate on loop.

How can I design well ?