I want he data model once with the data from all three requests UI5

Hi I want he data model once with the data from all three requests in Ui5, heres my Code, right under my code is my Solution Test but it didnt worked.

The Code:

onInit: function () {

            const tabletUrl = '/api/tablets?limit=1000&offset=0';

            fetch(tabletUrl).then(res => res.json()).then(res => {
                const dataModel = new JSONModel();
                dataModel.setData({
                    items: res
                });
                this.getView().setModel(dataModel, "aribadevices")

            })

            const notebookUrl = '/api/notebooks?limit=1000&offset=0';

            fetch(notebookUrl).then(res => res.json()).then(res => {
                const dataModel = new JSONModel();
                dataModel.setData({
                    items: res
                });
                this.getView().setModel(dataModel, "aribadevices")

            })

            const smartphonesUrl = '/api/smartphones?limit=1000&offset=0';

            fetch(smartphonesUrl).then(res => res.json()).then(res => {
                const dataModel = new JSONModel();
                dataModel.setData({
                    items: res
                });
                this.getView().setModel(dataModel, "aribadevices")

            })

I also tried this but it didnt worked:

const tabletUrl = '/api/tablets?limit=1000&offset=0';
const notebookUrl = '/api/notebooks?limit=1000&offset=0';
const smartphonesUrl = '/api/smartphones?limit=1000&offset=0';

Promise.all([fetch(tabletUrl), fetch(notebookUrl), fetch(smartphonesUrl)]).then(res => {
    const dataModel = new JSONModel();
    dataModel.setData({
        items: res.flat()
    });
    this.getView().setModel(dataModel, "aribadevices");
});