For anyone who want to use their own router instead of the SmartHub router/wifi functions. This is a tip to hopefully save others the hours of hold time and banging their head against the wall that I just went through.
TLDR: If you want to put a SmartHub model with an outdoor antenna (100 and 200 Mb/s plans) in bridge mode so that you can use your own router without conflicting with the Telus router, you need to bypass the Smarthub alltogether. Take the ethernet cable coming from the outdoor antenna and instead of plugging it into the cylindrical SmartHub, plug it directly into your router. Don't use the bridge mode setting in the SmartHub cylinder, that just makes it panic and turn off the internet.
The newest 5G SmartHub (Feb 2025 as I write this) for 100-200 Mbps plans has a setting for "bridge mode" but Telus has implemented it in a way that doesn't operate like normal bridge mode. If you turn it on, you lose all internet access.
It turns out that the modem hardware is in the antenna, not the cylindrical SmartHub, so you can just bypass the cylinder alltoghether and chuck the think. Plug the data port of the PoE injector direclty into your router instead of the SmartHub cylinder and voila, full speed internet without routing/NAT conflict.
If anyone from Telus reads this, please add this to your support doccumentation! The solutions that were offered were, to downgrade my service to a slower model that offers true bridge mode, or to set up a hacky workaround. There's absolutely no reason that a modem/router/AP unit shouldn't have bridge mode as an option. When I was considering signing up for SmartHub I called your service department to confirm that the unit could be put into bridge mode and they explicitly told me that it could. 3 hours on the phone later I was made aware of this workaround. It shouldn't be this hard to access a basic feature.
