✅ Finding all FieldInfo's of BackingFields of a type

FieldInfo[] doubleFields = t
    .GetProperties(BindingFlags.Public | BindingFlags.Instance)
    .Where(p => p.PropertyType == typeof(double))
    .Select(p => t.GetField($"<{p.Name}>k__BackingField", BindingFlags.NonPublic | BindingFlags.Instance)!)
    .Where(f => f is not null)
    .ToArray();