What Telus hardware do you have? Some installs have a single gateway/router like the Wifi Hub, and others have multiple devices including a separate ONT. I have 3 devices (ONT, T3200M, Boost Wifi 6). If there is more than one, you need to make sure all of them are powered to be able to connect.
As long as the fibre hardware outside your residence still has power when you lose yours, all of your hardware should still be able to connect as long as it has a functioning power source like the Jackery. If you lose cell service when your power goes out, there may be a bigger issue in your area. Cell towers should have a short term power backup or generator for larger sites. On the rare occasion my entire area loses power, cell service still works, and fibre does also as I have backup power for it.
Additionally, a Jackery is not an uninterruptable power supply. Some times when fibre hardware loses power, it can take some time to reconnect, assuming the area hardware is still online. An actual UPS would prevent your ONT/gateway from losing power. I have a proper UPS with my fibre terminal (ONT) and router connected and it stays online on the rare occasion the power drops here. There are also cheaper models of UPS out there. When I bought that model it was only $130 on sale but APC has notably increased prices since then. CyberPower would be a more cost effective alternative to get. I have one of their 750w units on some of my additional network hardware, including Telus' Boost Wifi 6, and my NAS. It has worked quite well.
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