Swift: How do I repeat a getDoc request to Firestore?

Question

I can already check if a doc exists in a collection. However I am unable to repeatedly check the same collection while trying different path names.

For example, my collection name is the UID of the user. There can be an unlimited amount of docs in this collection. The docs are titled "UID-0", "UID-1", "UID-2" and so on as the user adds items.

Every time it finds a doc that already exists such as "UID-0" it will change the path request to "UID-+=1" until the number exceeds the docs and it is able to create and use that path name.

Each doc contains about a dozen fields of the same data model but of course different data.

var docAlreadyExists: Bool = true
var multipleUserFencesIdCount: Int = 0
var newID: String = ""
let id = self.auth.currentUser?.uid ?? ""

repeat {
print("1")
self.fencesInfoCollection.document("Live").collection(id).document(newID).getDocument(completion: { document, error in
print("2")
    if let document = document, document.exists {
        print("EXISTS")
        multipleUserFencesIdCount += 1
        newID = newID.dropLast() + "\(multipleUserFencesIdCount)"
    } else {
        print("DOES NOT EXIST")
        docAlreadyExists = false
    }
})
} while docAlreadyExists

With that said, how can I repeatedly check if a document exists until the path name exceeds the rest and is able to create a new doc with the new data.

Edit:

The 1 gets repeatedly called correctly but the .getDoc never calls since 2 is never printed.