That is not true; you can hang on to the content URI and metadata to present a Recent Files UI. You need to ask for a persisted write permission for the content URI. You can even use the ContentResolver to check the file's existence and update the metadata (including thumbnail).
Although AFAIK Android's implementation then means that you can end up with duplicate entries for the same file if you open it through differing means (like both through an external file manager as well as within the app's own UI), because those result in distinct content URIs and there are no official APIs that would allow you to confirm whether two separate content URIs are actually pointing to the same file (where that'd make sense, e.g. for files on the local file system at least [1]).
[1] I think there are some hacks to work around that issue, but obviously they aren't guaranteed to work all of the time.
