How to reduce gap between 2 different items of a recyclerView?

Question

See this gap between the textViews of different items

There is a lot of spacing between the 2 different items in my recyclerView....Here is my xml Code...When I add every element like recycler View and textView and progressBar in a Linear layout then everything sticks to left top of the screen....please help

    `enter code here`
    <?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="#D500F9"
    tools:context=".Dogs_Diseases">

<androidx.recyclerview.widget.RecyclerView
    android:id="@+id/recyclerView"
    `android:layout_width="414dp"
    android:layout_height="652dp"
    android:background="#FBF7F7"
    android:elevation="?android:attr/scrollbarSize"
    app:layout_constraintBottom_toBottomOf="parent"
    app:layout_constraintEnd_toEndOf="parent"
    app:layout_constraintHorizontal_bias="0.0"
    app:layout_constraintStart_toStartOf="parent"
    app:layout_constraintTop_toBottomOf="@+id/textView2"
    app:layout_constraintVertical_bias="0.0" />


<TextView
    android:id="@+id/textView2"
    android:layout_width="219dp"
    android:layout_height="76dp"
    android:shadowColor="#D14141"
    android:text="Dogs"
    android:textAlignment="center"
    android:textColor="#00E5FF"
    android:textSize="34sp"
    android:textStyle="bold"
    app:layout_constraintBottom_toBottomOf="parent"
    app:layout_constraintEnd_toEndOf="parent"
    app:layout_constraintHorizontal_bias="0.453"
    app:layout_constraintStart_toStartOf="parent"
    app:layout_constraintTop_toTopOf="parent"
    app:layout_constraintVertical_bias="0.009" />


<ProgressBar
    android:id="@+id/progressBar"
    style="?android:attr/progressBarStyle"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:background="#751C1C"
    android:backgroundTint="#CC2121"
    app:layout_constraintBottom_toBottomOf="parent"
    app:layout_constraintEnd_toEndOf="parent"
    app:layout_constraintHorizontal_bias="0.922"
    app:layout_constraintStart_toStartOf="parent"
    app:layout_constraintTop_toTopOf="parent"
    app:layout_constraintVertical_bias="0.0" />

</androidx.constraintlayout.widget.ConstraintLayout>