my iCloud disappeared from my devices, can I get iCloud again anytime by establishing new iCloud account?

To subscribe for more storage, you would go into your iCloud settings -> this documents has the steps to do that -> Buy more iCloud storage - Apple Support

The extra storage applies to your iCloud account and AppleID so isn’t specific to any particular device.

There is no iCloud Drive app since iOS 11. Do you see a “Files” app? That is how you would access iCloud content.