Check this out. Relationship between Kobo and ODK
I am sure others will answer more definitively, but I think of KoBoToolbox as a more stable version of ODK with a very nice form builder interface. You can use forms created in the toolbox with either KoBoCollect (an android app) or Enketo/Web Forms which uses a browser, preferably Chrome. Apparently Firefox and others can be used.
With both KoBoCollect and Enketo, you need to be connected to the internet to be able to download new or updated forms. Then you can go offline to collect data and upload it when you are re-connected.
You can access your data by downloading an Excel file, but most larger organization will connect to the UN servers using APIs. However, this is not my area of expertise.
I have no knowledge of CSPro, so can’t help you there. However, KoBoToolbox is a real joy to work with, it appears very solid, and the support on this forum is amazing.