List<<List<string>> batches = splitListOfUrlStringsIntoBatches(urls, 50); // where 50 is the batch size

foreach (var batchList in listOfBatchLists)
{
    var insertForBatch = RunBatch(batchList);
    allInsertAmounts.Add(insertForBatch);
}

private int RunBatch(IEnumerable<string> batch)
    {
        var allWriteNum = 0;
        // this will run on one bound logical thread i think
        Parallel.ForEach(batch, (batchItem) => {
             var res = Client.GetAsync(batchItem.Item1).GetAwaiter().GetResult();
             var responseBody = res.Content.ReadAsStringAsync().GetAwaiter().GetResult();
             var strongType = JsonConvert.DeserializeObject<StrongType>(responseBody);

             dbContext.add(strongType);
             allWriteNum++
        });
        return allWriteNum;
    }