Where to put ShareReplay(1) pipe

I have the following call to Firebase database. If I want to share the result of the observable, where I'd I put the share really(1) ?

get userStacks(): Observable<StackModel[]> {
        return this.auth.authState
            .pipe(
                shareReplay(1), ===>>> HERE ?
                switchMap(user => {
                    if (user) {
                        return this.db
                            .collection<StackModel>('stacks', ref =>
                                ref.where('perm.readers', 'array-contains', user.uid),
                            )
                            .valueChanges()
                            .pipe(shareReplay(1),  ===>>> HERE ?
                                 stackList =>
                                combineLatest([
                                    stackList,
                                    this.dataService.currentNormalOrReverse,
                                    this.idsFilter$,
                                ]).pipe(
                                    shareReplay(1),  ===>>> HERE ?
                                    map(([stacks, normalOrReverse]) => [
                                        ...StacksService.sortAlphabetical(stacks, normalOrReverse),
                                    ]),
                                ),
                            );
                    }
                    return [];
                }),
            )
            .pipe(shareReplay(1)),  ===>>> HERE?
    }

I suppose it should be the last operation in the chain, just before I'd subscribe to the observable, therefore it should be the last on here. Is my assumption correct? Thank you.