ActiveForm for yii\httpclient\CurlTransport

I am trying to do CRUD operations but the data is not stored in the database. I am connecting to a third party api using yii\httpclient\CurlTransport - json format.

I was able to create READ operation with this request and put it on the GRIDVIEW dataprovider

$client = new Client(['transport' => 'yii\httpclient\CurlTransport',]);
        $request_sites= $client->createRequest()
            ->setData('primary_id' => $id)->setOptions([
                CURLOPT_CONNECTTIMEOUT => 5,
                CURLOPT_TIMEOUT => 10,
        $array_sites= Json::decode($request_sites->content);

My issue now is how can I work with UPDATE if my datasource is json and not a loaded MODEL.

<?= $form->field($model, 'sample')->textInput() ?>

For loading the data into the the form field I will need to create a request to the third party api. then once loaded the users should be able to update the form(which I think is another request to the third partyapi).

sample API endpoints: sites_add, sites_update, sites_delete

Is there any reference for sample implementation or documentation related to this?