Were both your laptop and TV access to YT running about the same speed at your old place, but now the laptop speed has increased, but not the TV's speed? Was the old place running on coax only?
The landlord may have wiring that does not include coax, which is traditionally slower and more finicky regarding distances and cable lengths, and which would explain the old place's lack of speed vs. neighbors, etc. How is your smart TV hooked up to receive the Internet? Did you get the Roku unit you were asking about before and use that?
If so, I can tell you that my Roku box / TV combo will freeze occasionally at different times of day or night depending on what the Internet via WiFi is doing in terms of traffic - and it only affects the Roku - not the laptop. Also, it seems to affect only certain channels like YT, or some of the streaming local news channels, who might not be using a fast connection to send stuff out. That is an important factor as well.
However, if your TV has an Ethernet port on it, and you can hook up to the WiFi router via an Ethernet port, you are much better off getting a CAT-5 Ethernet cable and hooking it up between the two. It should eliminate most if not all of the freezes, etc. you're now experiencing. Sometimes W-Fi packets get "lost" in the ozone and it then has to retransmit them, which is what causes the "freezing" while it's taking time for the replacement packets to get to your TV.
Unfortunately, that's only available on Roku 3/4 units, and mine is a 2, with a TV that has no Ethernet port. So I've actually gotten used to it (!) but it can be annoying.
If you did go with a Roku 3, you should be able to do this, assuming your WiFi box can take that cable input.
Sorry this was a bit long, but I hope it will help you with this issue. Good luck!