Voice Dream Reader and iCloud syncing query

iOS and iPadOS

hi all i have audio books stored with icloud sync in voicedream. firstly, if i turn this feature off, it seems it will delete all the files from voicedream on my ipad, is this correct? where can i find the files on icloud drive? i am also considering upgrading from my iphone 7, to the x, but if i get the 64 gb version, will icloud sync still stay on if i have to reset this phone and put voicedream on a new phone? the files are not stored on the device by default are they, they are just downloaded een i ask voicedram to get them? Will S for