I am trying to reverse my recyclerview items but neither setReverseLayout nor Collection.reverse() works

I have an app trying to show its items from the latest item added to earlier ones in a grid view with GridLayoutManager, getting the items from firebase database, setReverseLayout works but when the items are not uniform or items total is an odd number, it leaves a vacant space for on item at the top like it omitted an item but it didnt, i tried using collections.reverse but it didnt really arrange the items from latest items, more like shuffled it and i still have that gap problem at the top. There is no error message, the app runs fine but its not displaying items the desired way.

Here is a screenshot of the problem with both methods I tried

Here is my recycler adapter code

package com.example.twelve.Adapters;
import android.content.Context;
import android.content.Intent;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageView;
import android.widget.TextView;
import androidx.annotation.NonNull;
import androidx.recyclerview.widget.RecyclerView;
import com.example.twelve.HomeActivity;
import com.example.twelve.Model.HomeProducts;
import com.example.twelve.Products_Page_Activity;
import com.example.twelve.R;
import com.squareup.picasso.Picasso;
import java.util.ArrayList;
import java.util.List;
public class RecyclerAdapter extends RecyclerView.Adapter<RecyclerAdapter.ViewHolder> {
List<HomeProducts> lstproducts = new ArrayList<>();
Context ncontext;
public RecyclerAdapter(List<HomeProducts> lstproducts, Context ncontext) {
this.lstproducts = lstproducts;
this.ncontext = ncontext;
}
@NonNull
@Override
public ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
return new ViewHolder(LayoutInflater.from(ncontext).inflate(R.layout.home_product_items, parent, false));
}
@Override
public void onBindViewHolder(@NonNull ViewHolder holder, final int position) {
holder.cardview_pname.setText(lstproducts.get(position).getPname());
holder.cardview_category.setText(lstproducts.get(position).getCategory());
holder.cardview_price.setText(lstproducts.get(position).getPrice());
Picasso.get().load(lstproducts.get(position).getImageurllist().get(0)).into(holder.cardview_image);
holder.itemView.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
Intent intent = new Intent(view.getContext(), Products_Page_Activity.class);
intent.putExtra("pid", lstproducts.get(position).getPid());
intent.putExtra("prev_activity", "Home");
view.getContext().startActivity(intent);
}
});
}
@Override
public int getItemCount() {
return lstproducts.size();
}
public class ViewHolder extends RecyclerView.ViewHolder {
public ImageView cardview_image;
public TextView cardview_pname, cardview_category, cardview_price;
public ViewHolder(@NonNull View itemView) {
super(itemView);
cardview_image = itemView.findViewById(R.id.rec_imgview);
cardview_pname = itemView.findViewById(R.id.rec_textviewname);
cardview_category = itemView.findViewById(R.id.rec_textviewcategory);
cardview_price = itemView.findViewById(R.id.rec_textprice);
}
}
}

Code to add products to the adapter

//Products are added in a list and passed to the adapter
DatabaseReference pref = FirebaseDatabase.getInstance().getReference("HomeProducts");
pref.addValueEventListener(new ValueEventListener() {
@Override
public void onDataChange(@NonNull DataSnapshot snapshot) {
for(DataSnapshot dataSnapshot : snapshot.getChildren()){
HomeProducts Hproducts = dataSnapshot.getValue(HomeProducts.class);
listtems.add(Hproducts);
Collections.reverse(listtems);
}
rcyAdapter = new RecyclerAdapter(listtems, HomeActivity.this);
rcyAdapter.notifyDataSetChanged();
recyclerView.setAdapter(rcyAdapter);
}
@Override
public void onCancelled(@NonNull DatabaseError error) {
}
});

you should use setStackFromEnd :

GridLayoutManager manager = new GridLayoutManager(this, 2);

manager.setStackFromEnd(true);

try to get Collections.reverse(listtems); out of the for loop .. just after its end brace to complete getting all the items of the collection first and then reverse it