Values set in Inspector for prefab reset after restarting Unity

I am creating a prefab for a stylized input, which proxies properties to the underlying game objects that make up the input parts. (Using NovaUI for some parts)

Here is my script for the UnderlinedTextInput:

using Nova;
using UnityEngine;

public class UnderlinedTextInput : MonoBehaviour
{
  [SerializeField]
  public Color32 TextColor
  {
    get => _InputField.Color;
    set => _InputField.Color = value;
  }
  [SerializeField]
  public string Text
  {
    get => _InputField.Text;
    set => _InputField.Text = value;
  }

  [SerializeField]
  public Color32 PlaceholderColor
  {
    get => _Placeholder.Color;
    set => _Placeholder.Color = value;
  }

  [SerializeField]
  public string Placeholder
  {
    get => _Placeholder.Text;
    set => _Placeholder.Text = value;
  }

  [SerializeField]
  public Color32 LabelColor
  {
    get => _Label.Color;
    set => _Label.Color = value;
  }
  [SerializeField]
  public string Label
  {
    get => _Label.Text;
    set => _Label.Text = value;
  }

  [SerializeField]
  public Color32 UnderlineColor
  {
    get => _Underline.Color;
    set => _Underline.Color = value;
  }


  [Header("Prefab Editing-Only")]
  [SerializeField] private TextBlock _InputField;
  [SerializeField] private TextBlock _Placeholder;
  [SerializeField] private TextBlock _Label;
  [SerializeField] private UIBlock2D _Underline;
}

And here is the Editor script:

using UnityEngine;
using UnityEditor;

[CustomEditor(typeof(UnderlinedTextInput))]
public class UnderlinedTextInputEditor : Editor
{
  public override void OnInspectorGUI()
  {
    UnderlinedTextInput inputComponent = (UnderlinedTextInput)target;
    bool isEditingPrefab = PrefabUtility.GetPrefabInstanceStatus(inputComponent) == PrefabInstanceStatus.NotAPrefab;

    CheckForInputChanges(inputComponent);
    DrawEditorFields(isEditingPrefab);
  }

  private void DrawEditorFields(bool isEditingPrefab)
  {
    EditorGUILayout.BeginVertical();
    // only show all the properties if we are editing the prefab
    if (isEditingPrefab)
    {
      // draw everything else
      DrawDefaultInspector();
    }

    EditorGUILayout.EndVertical();
  }

  private void CheckForInputChanges(UnderlinedTextInput inputComponent)
  {
    EditorGUI.BeginChangeCheck();

    string text = EditorGUILayout.TextField("Text", inputComponent.Text);
    string placeholder = EditorGUILayout.TextField("Placeholder", inputComponent.Placeholder);
    string label = EditorGUILayout.TextField("Label", inputComponent.Label);
    Color32 labelColor = EditorGUILayout.ColorField("Label Color", inputComponent.LabelColor);
    Color32 underlineColor = EditorGUILayout.ColorField("Underline Color", inputComponent.UnderlineColor);
    Color32 placeholderColor = EditorGUILayout.ColorField("Placeholder Color", inputComponent.PlaceholderColor);
    Color32 textColor = EditorGUILayout.ColorField("Text Color", inputComponent.TextColor);

    if (EditorGUI.EndChangeCheck())
    {
      inputComponent.Text = text;
      inputComponent.Placeholder = placeholder;
      inputComponent.Label = label;
      inputComponent.LabelColor = labelColor;
      inputComponent.UnderlineColor = underlineColor;
      inputComponent.PlaceholderColor = placeholderColor;
      inputComponent.TextColor = textColor;

      EditorUtility.SetDirty(inputComponent);
      Undo.RecordObject(inputComponent, "Modify UnderlinedTextInput Properties");
    }
  }

  private void DrawPrefabInstanceInspector(UnderlinedTextInput inputComponent)
  {
    EditorGUILayout.ColorField("Label Color", inputComponent.LabelColor);
    EditorGUILayout.TextField("Label", inputComponent.Label);

    EditorGUILayout.ColorField("Placeholder Color", inputComponent.PlaceholderColor);
    EditorGUILayout.TextField("Placeholder", inputComponent.Placeholder);

    EditorGUILayout.ColorField("Text Color", inputComponent.TextColor);
    EditorGUILayout.TextField("Text", inputComponent.Text);

    EditorGUILayout.ColorField("Underline Color", inputComponent.UnderlineColor);
  }
}

I’m fairly new to Unity, but my guess is that I’m not properly marking the instantiated prefab as dirty. That, or something about using getter/setters for Inspector fields doesn’t allow Unity to save those values? Anyways, is there something I can change to make this work, or is this not a supported workflow?

Thank you in advance!