Error: Missing or insufficient permissions - firebase

Question

I got a firestore like this:
:stores
|
$Store
:orders
|
$Order
:items
I want to read orders from my database using a user having an workerUid same as the request.auth.uid but geht the Error: Missing or insufficient permissions.
The important part of my firebase rules:
service cloud.firestore {
match /databases/{database}/documents {
//Matches any document in the stores collection
match /stores/{store} {
function isStoreAdmin(uid) {
return get(/databases/stores/$(store)).data.adminUid == uid;
}
function isStoreWorker(uid) {
return get(/databases/stores/$(store)).data.workerUid == uid;
}
allow read: if request.auth.uid != null;
allow write: if request.auth.uid == resource.data.adminUid;
//Matches any document in the orders collection
match /orders/{document=**} {
allow read, write: if isStoreAdmin(request.auth.uid) || isStoreWorker(request.auth.uid);
}
}
}
}
Funny thing is, that it works if I do this:
match /orders/{document=**} {
allow read, write: if isStoreWorker(request.auth.uid);
}
or this:
match /orders/{document=**} {
allow read, write: if request.aut.uid != null;
}
When deploying the rules I get no syntax error so I really can't understand why this is not working. Does anyone have any ideas? Thank you so much!
Edit:
function readAllDocuments(collectionReference, callback,finishedCallback){
collectionReference.get().then(function(querySnapshot) {
querySnapshot.forEach(function(doc) {
callback(doc.id,doc.data());
});
finishedCallback();
});
}
const storeDocument = getRootCollection(STORES_COLLECTION_ID).doc(storeId);
const orderCollection = storeDocument.collection(STOREORDERS_COLLECTION_ID);
orders=new Map();
readAllDocuments(orderCollection, function (id, data) {
orders.set(id,data);
},function(){
finishedLoading();
});

Answer 1

The documentation for use of get() in a security rule states:
...the path provided must begin with /databases/$(database)/documents
Make these changes to the get() paths:
function isStoreAdmin(uid) {
return get(/databases/$(database)/documents/stores/$(store)).data.adminUid == uid;
}
function isStoreWorker(uid) {
return get(/databases/$(database)/documents/stores/$(store)).data.workerUid == uid;
}