The Huawei B618 is above my budget unfortunately. I didn't buy the TP Link one on random though. I followed the list of recommended modems in the Digi Infinite 150 main thread. However, I didn't buy a prepaid sim and try first. You're right that I should have.

That said, Digi Infinite 150 is literally the only viable option in this area. Either that or I shell out nearly 3K to get 20 Mbps fibre internet.