افزودن prepare به متد ها

این متد خود exec درون همین پکیجیه که دارید استفاده میکنید

public function exec(string $statement, array $map = [], callable $callback = null): ?PDOStatement
    {
        $this->statement = null;
        $this->errorInfo = null;
        $this->error = null;

        if ($this->testMode) {
            $this->queryString = $this->generate($statement, $map);
            return null;
        }

        if ($this->debugMode) {
            if ($this->debugLogging) {
                $this->debugLogs[] = $this->generate($statement, $map);
                return null;
            }

            echo $this->generate($statement, $map);

            $this->debugMode = false;

            return null;
        }

        if ($this->logging) {
            $this->logs[] = [$statement, $map];
        } else {
            $this->logs = [[$statement, $map]];
        }

        $statement = $this->pdo->prepare($statement);
        $errorInfo = $this->pdo->errorInfo();

        if ($errorInfo[0] !== '00000') {
            $this->errorInfo = $errorInfo;
            $this->error = $errorInfo[2];

            return null;
        }

        foreach ($map as $key => $value) {
            $statement->bindValue($key, $value[0], $value[1]);
        }

        if (is_callable($callback)) {
            $this->pdo->beginTransaction();
            $callback($statement);
            $execute = $statement->execute();
            $this->pdo->commit();
        } else {
            $execute = $statement->execute();
        }

        $errorInfo = $statement->errorInfo();

        if ($errorInfo[0] !== '00000') {
            $this->errorInfo = $errorInfo;
            $this->error = $errorInfo[2];

            return null;
        }

        if ($execute) {
            $this->statement = $statement;
        }

        return $statement;
    }

داخلش prepare استفاده شده و نیازی نیست خودتون prepare کنید 

درود

این متد تو دل خودش queryها رو prepare میکنه لازم نیست همچین کار کنید