I went ahead with a Wifi extender, and it's not really working great, mostly due to sparse outlets. One or two bars at best. Very weak. And slow. Thus, the power line adapters may be my only solution. I have a question about the Powerline adapters. The upstairs apartment is on a separate breaker, but I think is daisy-chained off the main breaker. How does this affect things?
So it might help to understand that the Extenders usually cut your actual throughput in half,just the nature of the beast.They usually use the same radio inside to make the WiFi connections to your other main unit and then also to your computers but they can not do them at the same time and so they time share the signal through the radio and cut performance in half in the best circumstances.So they developed the Mesh systems for WiFi which I am sure you have heard of and these now all use seperate radios inside to keep the two things that they do at full speed and usually they will give much better performance than a simple extender.I didnt catch what your main WiFi is either and often the only full speed way to extend WiFi is with a matching extender or Node that is from the same manufacturer as your WiFi base.Again though you dont mention or I didnt understand where your existing cable entry and router and existing WiFi is and you will need to connect any new system there.I use Ubiquity Mesh Systems all the time and they have an entry level system sold as AMPLIFY wireless and the nodes are each about $100 and they work so well that you might even be OK with just a single unit and no extender as in many installs they so outperform the one you get from the cable company that it is all you need but they are also scalable and can Mesh wirelessly or wired pretty easily and I imagine could easily solve you problems if you can find one.Lately I have used a new system called Vilo that is under $70 for a 3 node Mesh system which is a crazy new low price point and another worth looking into.The only drawback is that you will need to setup your existing system to not operate and connect the new one to your router so it can be configured as your system.You can do this all from a phone but it is easier for some people than others so know in advance what you are getting into if you dont have experience with these things. They are pretty simple but........YMMV too.