xFi Gateway signal has got weaker

In the last 6 months to a year my wifi signal strength has got increasingly slow. When I moved into this house, all worked perfectly. Now, my work station / bedroom office (same place its always been) is getting -87 dBm. I am at the farthest point away from my gateway, but it worked way better when I first moved in. No extra devices have been added in the same time frame. I have a pod coming in a couple days, but I'd like to address the real problem, if there is one. I included two photos of my router info, do these tell a story? Appreciate the feedback

[Edited: "Personal Information"]