I've not used Cloudinary but from a quick look, it seems to be more of a CDN which means it manages the files but they are not actually 'stored' on the device the user has.
To do what I think you want, you will need to use a service worker to create and manage cached files (html, scripts, images) so that the user can carry on offline. I have used Workbox before to do this. It will also have the benefit, if done correctly, of allowing users to install your app as a full PWA.
You will need to create a manifest, service worker and webapp script as well as making some modifications to the meta tags and header code. It's not to extreme and I think this thread might be a good place to start:
(it was created a little while ago and a few things have changed in the Wappler UI, but it should give you a good idea to work from)