golang issue when parsing data to bson for mongodb

I am having a strange (to me) an issue with golang mongodb connector. The current problem is that I have a db retrieval function that actually returns no errors, but the struct expected is just not there (null). Here is part of the code that will probably give some hints:

[library]

func (db *NoSqlConnection[T]) CreateRecoveryTable(p *player.Player[T]) error {

    updt := bson.M{"id": p.Id}
    _, err := db.db.Collection(recoveryTableName).InsertOne(context.TODO(), updt)

    if err != nil {
        return fmt.Errorf("failed to update recovery state ")
    }
    return nil
}

func (db *NoSqlConnection[T]) AddRecoveryRecord(p *player.Player[T], record *recovery.Recovery[T]) (int64, error) {
    opts := options.UpdateOne().SetUpsert(true)
    updt := bson.M{"$set": bson.M{"game_id": p.GID, "record": record}}
    _, err := db.db.Collection(recoveryTableName).UpdateOne(context.TODO(), bson.M{"id": p.Id}, updt, opts)
    if err != nil {
        return -1, fmt.Errorf("failed to update recovery state")
    }

    return 1, nil
}

func (db *NoSqlConnection[T]) GetPlayerRecoveryById(id T) (recovery.Recovery[T], error) {
    filter := bson.M{"id": id}
    res := recovery.Recovery[T]{}
    err := db.db.
        Collection(playersTableName).
        FindOne(context.TODO(), filter).
        Decode(&res)

    if err != nil {
        if err == mongo.ErrNoDocuments {
            return res, err
        }
        return res, err
    }
    return res, nil
}

The problematic function is GetPlayerRecoveryById(id T) Other functions work correctly (creating / updating the records in my atlas test db).

The recovery model is as:

type SpecializedID interface {
    int64 | uint64 | uuid.UUID | string
}
...

type Recovery[T models.SpecializedID] struct {
    Id     T   `json:"id" bson:"id"`
    Record any `json:"record" bson:"record"`
}

So when I try to retrieve the record I never get an error, as I expect to have, but always get a zerofill record. I've tried almost all printing families , but can't seem to understand why there is nothing inside the that struct. What I am missing here?