I mostly agree with the above- except the part about buying just any router.
If you really cannot get one run of ethernet run upstairs somewhere in the house- something I doubt if both you and landlord are $$$ motivated (you for a reliable connection and landlord for a new benefit to pitch to future renter candidates)... especially if you 100% pay to have it done and make it look as "pretty" as possible when finished (an ethernet wall jack at both connection points- you need to identify exactly WHICH kind of router landlord has. If it is a mesh router, buy a matching extender for that unit (as HDFan says in the prior post).
If landlords router is old/non-mesh, pitch buying a "latest & greatest" Wifi 6 or better mesh router replacement. If you 100% pay for it (to eliminate any cost concern from a potentially penny-pinching landlord), landlord should welcome the "free" hardware upgrade (to maximize their own wifi downstairs too). Hook router up downstairs and extender(s) upstairs. If you get one with 2 extenders, put one close to AppleTV and plug AppleTV into the ethernet jack on the extender so you can bypass wifi usage for AppleTV within your own space (unfortunately, mesh is still using wifi to connect to the router downstairs, so if there is some odd interference cause around, this may not resolve your issue (which again points back to one run of ethernet from landlords router to your space).
An extender (as also just recommended by HDFan) is another option that I know first hand can work pretty well. It differs from a mesh extender by not necessarily being from the same mesh product line or even the same manufacturer. Nevertheless, it functionally works similar to mesh though it too is at the mercy of getting wifi from downstairs to it and whatever the interference may affect that too. The best option with an extender is (again) to use one run of ethernet from router to it to bypass any floor-to-floor interference.
As also offered in your prior threads,
ethernet over power lines can work great (not as great as one run of ethernet cable down the inside of the wall but better than nothing)... a way to kind of run an ethernet connection up to you without having to actually get an ethernet cable in the wall (using existing electrical lines instead). In a situation like yours, I've set someone up with this solution to make for better AppleTV usage and it worked fine. Basically, this is:
- 2 little boxes plugged into an electrical jack on the wall, one downstairs near landlords router and one upstairs (almost) wherever you like it.
- Plug an ethernet cable from router into an ethernet jack on one power line box downstairs.
- Plug an ethernet cable from power line box upstairs either directly into your AppleTV or ANY wifi router you like upstairs.
- Check signal (speed test). If no signal, try a different power jack upstairs or maybe a few until you find a solid signal. Not every electrical jack is likely to work. Both ends have to be on the SAME circuit. So move your box around and test connection until you find an outlet on the same circuit as the landlords end.
To keep this simple, from your powerline ethernet box, plug right into AppleTV and see if you have a signal (then run speed test). If you do, either leave it as a dedicated AppleTV solution or add your own router to that ethernet connection and then connect your AppleTV to your own router via Ethernet. This will give you your own wifi network upstairs as well as a fast ethernet connection for your AppleTV.
This is easy enough to buy & try (with simple landlord cooperation). If it works, problem likely solved. If it doesn't return this product and try one of the others. This probably won't yield internet as fast as a dedicated run of ethernet but it should be fast enough for your usages described in several threads about this.
Lastly,
MOVE. I don't recall your first post about this but you have to be getting close to your rental anniversary. My gut guess is your first post about this "feels" like it was about 6+ months ago or so. If landlord won't work with you to deliver a solid solution (which I still argue at least ONE run of ethernet in the wall as very best option), move and choose a place with a broadband option that doesn't have you dependent on somebody else's modem & router. A solid Internet connection is obviously very important to you. One of the best things about being a renter is the easy ability to move when a rental space is no longer working for you. If you choose this option, make your new rental search include a priority to show you how you are going to have your own modem, router hookup so you can completely control all 100% of the wifi bandwidth instead of sharing only a portion of someone else's. Move into that space, hook up high quality modem & router hardware and completely resolve this problem without needing any favors from anyone else.
One more thing: roommates not being physically there doesn't mean they are not eating bandwidth. I'm traveling right now but regularly logging into the home system to transfer some files, I have a DVR system recording favorite shows and storing them on a network drive, security system is watching the property and recording any movement, etc.
While I built the home and run Ethernet to almost everything, a few things have to lean on wifi. If I didn’t wire everything, much more would be using wifi instead.
So even though I'm not there, some wifi is being used. What if your roommates are doing the same? What if landlord has some wifi things using bandwidth even when they are not there (security stuff? Etc.). If they are on vacation, what if they are remotely transferring photos & videos they are taking to their home machine over wifi? Etc. There's LOTS of possibilities.
