I had a technician come install fibre service. Because the modem is encased in the wall, I told him I needed wired access to it for gaming. He kept swearing up and down that wireless does not cause any issues or drops in performance.
I ran two speedtests.
...he still didn't believe me. I honestly think he just didn't want to put a Cat5 jack where the RJ-11 jack. was (despite the fact that the RJ-11 jack was wired with Cat5 cable)