I have a Spectrum home wifi modem connected to a TP-Link router right next to a wall, behind which is my PC. I noticed over the last few months that my internet has been very slow and spotty, which is a concern because I use GeForce NOW to play a lot of demanding titles. My speeds before looked like 90mbps download and ~15-20mbps upload. A month or so in, my speeds dropped to 15-30mbps download and 2mbps upload. Now, they've recovered, but my actual experience remains almost identical.
My first thought was that buffer-bloat had to be the issue, but after testing with ethernet and regular wifi WITHIN DIRECT LINE OF SIGHT of the router, nothing was different. When I move back behind a wall, though, my internet starts getting slow and laggy, even stopping altogether sometimes. It is also worth mentioning that my wireless AP has gone down altogether periodically throughout this whole time, which I know because I get this lovely screen saying "WLAN Connection Lost!". When testing on my iPhone, Android phone, and iPad, results are always similar to my PC.
I don't know a lot about internet and the inner workings, but I'll try to provide extra details if needed. If you all have any advice, please let me know. I'm currently burning $20 a month on GeForce NOW and can't play anything.