It is recited: as you say, with the ت and the ي. And then it indicates that what follows, which is لَابْتَغَوْا, is a response to the words of the polytheists and a consequence of 'if'. And the meaning of لَابْتَغَوْا إِلى ذِي الْعَرْشِ سَبِيلًا is that they sought a way to the One who has sovereignty and lordship by overpowering, as kings do with one another. As His saying goes: 'If there were in them gods except Allah, both would have certainly been corrupted.' It is also said: to draw near to Him, as in His saying: 'Those are the ones who invoke, seeking a means to their Lord.' The term عُلُوًّا means exaltation in the sense of being above. The intended meaning is to be free from that and to be pure. And the meaning of describing exaltation with greatness is an emphasis on the meaning of being free and distant from what they described Him with.