I am guessing this point is totally unnecessary based on how overall well-informed your comment was, but in case you weren’t aware, it is frequently helpful to run a wifi analyzer of some sort to figure out which channels are heavily utilized in your area so you can set your router to one with less interference. I used to use the Mac network utility that I think may have been deprecated, but it worked like a charm. I do this for my friends all the time and it dramatically improves their network performance in 90% of cases. The only places I found it was pointless were in the middle of nowhere and my own apartment not too far from MIT’s campus, where I assume I was surrounded by equally (probably much more) knowledgeable nerds so the neighboring networks were surprisingly evenly distributed across the available channels.