It's strange that the tech told you the BYO Asus router might work. I just tried to set up a Netgear LAX-20 4g router on my rural Smart Hub plan and was told by tech support that no BYODs are allowed at all. The Netgear should work (proper LTE bands), and in fact I managed to access a "device not compatible" Telus web page, which suggests that it does connect. But the phone rep said they could not activate/permit the device at all.
But that's the thing with Telus support: ask 5 guys, get 5 answers, and always with the impression that they're just reading scripts without really knowing anything.
Anyone had luck activating a BYOD router on the rural Smart Hub network?