Serializing the Event property of class XXX : Cannot create an abstract class with Identity Server and MongoDB

Question

I have a property in my MongoDB document which is the base class for the event raised from IdentityServer public Event Event { get; set; } = null!; the Event is an abstract class that cannot be instantiated and have some derived types implemented in the IdentityServer package,

I got this exception when trying to get data:

System.FormatException: An error occurred while deserializing the Event property of class XXX: Cannot create an abstract class.
 ---> System.MemberAccessException: Cannot create an abstract class.
   at System.Runtime.CompilerServices.RuntimeHelpers.GetUninitializedObject(Type type)
   at MongoDB.Bson.Serialization.BsonClassMap.<GetCreator>b__118_2()
   at MongoDB.Bson.Serialization.BsonClassMap.CreateInstance()
   at MongoDB.Bson.Serialization.BsonClassMapSerializer`1.DeserializeClass(BsonDeserializationContext context)
   at MongoDB.Bson.Serialization.BsonClassMapSerializer`1.Deserialize(BsonDeserializationContext context, BsonDeserializationArgs args)
   at MongoDB.Bson.Serialization.Serializers.SerializerBase`1.MongoDB.Bson.Serialization.IBsonSerializer.Deserialize(BsonDeserializationContext context, BsonDeserializationArgs args)

to avoid this issue I've tried adding [BsonKnownTypes(typeof(X),typeof(Y))] attribute to my property,

regarding that, if any new derived type is added to a future version of IdeneityServer which is not included in my BsonKnownTypes, is this the best solution? what else can I do?