Telus Boost & Amazon Devices

I have the brand new Arcadyan Fibre AC Gateway Modem/Router with 4 Wifi Boosts. All my Apple products work perfect (ie. iPhone, iPad, Apple TV, Macbooks). No drop outs. Great signal strength. That is not the case for my Amazon Echo devices. I have 6 Echo 2nd Generation devices and 2 Echo Dot 3rd Generation devices. The problem is my Echo devices drop out a lot. I read on Amazon that they need to be on a 2.4GHz network. On the Arcadyan Fibre Modem/Router there is a 5GHz-Low network, and for some reason, my Echo devices keep connecting to the 5GHz-Low instead of the 2.4GHz. I disabled the 5GHz-Low, but the Wifi Boost discounted and will not work without the 5GHz-Low. So, I was wondering if anyone knows how to use a MAC address for the devices. I noticed that each Boost has a MAC address for a 2.4GHz and a 5GHz. So, I am hoping someone can give me a step-by-step guide on how to insert MAC addresses.
I know you cannot separate the 2.4 and 5GHz on the Boosts. But, I am hoping by inserting the 2.4GHz MAC address to my Echo devices that this will work. I talked to Telus representatives. They do not know anything about this new modem, and they barely know anything about the Wifi Boosts. So, I am reaching out to the Community to help me in a last resort before I get rid of my Telus Boost Wifi system.
Thank you so much. Look forward to hearing responses.