How to increase download speed of my Laptop

Speeds with wifi are never guaranteed. Between the basement and main floor you will have a lot of things that can interfere with wifi. Electrical, plumbing, HVAC, and even flooring materials, kitchen appliances, etc., can make a difference. If there are appliances between where you are in the kitchen and where the Boost 7 is, that is going to have a big impact

Getting a second access point, like a Boost, to put upstairs would help. Not a router but a wireless access point. A second Boost unit could work but you'd need a way to physically connect it to your existing Telus hardware for best results. A Boost 6 is slower than the 7. Don't try to get them to replace the Boost 7 as it's working. They will likely charge for that tech visit.

Additionally, changing which network frequency you are using can also make a difference. Higher frequencies can be interfered with easier. A lower frequency like 2.4GHz would have less interference but it's also used for slower wifi. You could always re-locate where the Boost is in the basement. Are you able to place it directly below the kitchen, if it's not already?