he MongoDB EF Core Provider currently rejects [BsonIgnoreIfNull].

Please support omitting null-valued properties when inserting documents through SaveChanges / SaveChangesAsync, preferably through a per-property attribute and/or fluent model configuration.

This is important for backward compatibility with existing documents when entities evolve and gain new optional properties. New properties should be absent from BSON documents when null, rather than persisted as explicit BSON null values.

Please also clarify the expected behavior when an existing, non-null property is explicitly changed to null: storing BSON null versus removing the field with $unset should have well-defined semantics.