C# MongoDB update definition from filled model

How i can combine type C# filled model and mongo language for create update request?

i try this but get types error:

var update = new ObjectUpdateDefinition<User>(user) & Builders<User>.Update.Inc(f => f.FindCount, 1);

FullCode:

            var user = new Model
            {
                Email = email,
                Language = language,
                Password = password,
                // +17 fields
            };
            
            // how i can convert all fields to set? and join with query Inc (like AllFieldToSet)? 
            var update = user.AllFieldToSet() & Builders<User>.Update.Inc(f => f.FindCount, 1);
            
            Models.FindOneAndUpdate<Model>(
             f => f.Email == email, 
             update, 
             new FindOneAndUpdateOptions<Model> {IsUpsert = true});