Elements in the inspector must use the alignedFieldUssClassName class (a field on any class inheriting from BaseField<T>) to receive the styling that aligns their labels to the same depth.
Add the class to the root VisualElement field that contains your label and control.
Unity, huh, how?
public override VisualElement CreatePropertyGUI(SerializedProperty property)
{
LayerField layerField = new LayerField(property.displayName) { bindingPath = property.propertyPath };
layerField.AddToClassList(AlignedFieldUssClassName);
return layerField;
}
// Use the implementation that works for your version.
// Any type that inherits from BaseField<T> can be used.
public static readonly string AlignedFieldUssClassName =
#if UNITY_2022_2_OR_NEWER
BaseField<int>.alignedFieldUssClassName;
#else
BaseField<int>.ussClassName + "__aligned";
#endif