You can’t do much with scrivener as messing with its .scriv files is dangerous. However there are two options (both of which I use).
In scrivener you can ‘sync to external folder’ and then index that into DT. Any changes in the folder from either Scrivener or DT will show up in both. If that folder is on iCloud, you can use IOS editors. E.g. I have a scrivener project that syncs to an ICloud folder within IA Writer. Anything in this folder I can access in Scrivener, DT or IA writer (MacOS or IOS).
The second option is to put the Scrivener’s scratchpad into a folder on iCloud and index it with DT. You can then add documents to the scratchpad using DT or using a shortcut like @DTLow on IOS or have the scratchpad folder within the iCloud of your editor of choice.
FYI copying DT item links into a scrivener document (say in your reference section) also work to open the DT items.
FYI (2) I store scrivener projects within a DT database. I haven’t had any issues so far.