Jednostki SP używamy tylko dla tekstu, a w innych sytuacjach DP.
Tworzysz layout w ConstraintLayout, a widokom ustawiasz dla szerokości i wysokości wrap_content. To tak nie zadziała. Podaj tam 0dp zamiast wrap_content. Inaczej twój tekst będzie ucinany.
Zobacz jak ja to zrobiłem.
<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.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:id="@+id/relativeLayout"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#3A5B14"
tools:context=".MainActivity">
<ImageView
android:id="@+id/imageView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="16dp"
android:onClick="loadBasicActivity"
android:scaleType="centerInside"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toLeftOf="@+id/imageViewText"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias=".25"
app:srcCompat="@drawable/logo_big" />
<TextView
android:id="@+id/imageViewText"
android:layout_width="0dp"
android:layout_height="0dp"
android:layout_marginStart="16dp"
android:layout_marginEnd="16dp"
android:gravity="center_vertical"
android:text="Związek\nHarcerstwa\nRzeczypospolitej"
android:textColor="#2B2B29"
android:textSize="26sp"
android:textStyle="bold"
app:layout_constraintBottom_toBottomOf="@+id/imageView"
app:layout_constraintLeft_toRightOf="@+id/imageView"
app:layout_constraintRight_toRightOf="parent"
app:layout_constraintTop_toTopOf="@+id/imageView" />
<ImageView
android:id="@+id/imageView3"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="16dp"
android:clickable="true"
android:onClick="loadBasicActivity"
android:scaleType="centerInside"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintHorizontal_chainStyle="spread"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toLeftOf="@+id/imageViewText3"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias=".75"
app:srcCompat="@drawable/logo_small" />
<TextView
android:id="@+id/imageViewText3"
android:layout_width="0dp"
android:layout_height="0dp"
android:layout_marginStart="16dp"
android:layout_marginEnd="16dp"
android:gravity="center_vertical"
android:singleLine="false"
android:text="Naciśnij logo ZHR, aby kontynuować"
android:textColor="#2B2B29"
android:textSize="24sp"
app:layout_constraintBottom_toBottomOf="@+id/imageView3"
app:layout_constraintLeft_toRightOf="@+id/imageView3"
app:layout_constraintRight_toRightOf="parent"
app:layout_constraintTop_toTopOf="@+id/imageView3" />
<ImageView
android:id="@+id/imageView2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_margin="32dp"
android:onClick="loadBasicActivity"
android:scaleType="centerInside"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintHorizontal_bias=".85"
app:layout_constraintRight_toRightOf="parent"
app:layout_constraintVertical_bias=".85"
app:srcCompat="@drawable/logo_cross" />
</android.support.constraint.ConstraintLayout>