Look here anyone who's knowledgeable about Internet, PS4, or just tech in general - I have a questio

The only thing I can think of, is that your router's wifi is faster then its physical connection. As for reliability, that would depend on the length of the cord and the cord itself.

What router do you have? And how old is the cord your using?

This is why.

Ok, before we go any further we need to do some basic trouble shooting. Before that though, I need to know what you have available to you, to trouble shoot with.

So, what is the age of the cable your trying to use? How many ports is your router using? And have you ever messed with the configuration of the router?

the problem is either your router has a firewall thats specifically blocking his ability to watch or the powerline adaptors crapping out (which every type does) its 99% likely to be the powerline adaptors causing the problem, they are inhernatly a crap invention for anything other than the most basic consumption only connection, it is far better to get a series of long Ethernet leads (up to 25meters in length of shielded cat 6) and if necessary to give longer reach a couple of simple unmanaged switches (for reference i have 5 simple unmanged switches and 3 25 meter long runs between them provding a total of 30 connections to a single port on my router and all of them run at 1gbps connection speeds) 

another common problem with powerlines is they are essentially a complete access solution to a private network loop and add in header information to the transport stream some routers strip this out before onwards transmission others strip it out when receiving the information some leave it in on both sides which then becomes a problem if the receiver has the same brand of powerline adaptors in their home setup and you both are running in the default setup for them..... oh and since there powerline adaptors changing them from the default setup often means they crap out more frequently or wont work at all until you do the factory reset on them...

then of course is the just for shits and giggles factor, unless you have a one way diode on your electrical connection you can inadvertently share your internet with any other powerline user within 100meters of you.... made for fun times when one guy couldn't figure out how he was using up his internet allowance in a single day in a tower block i can tell you ....

This is a crazy idea but have you tried disabling the wifi completely and trying with LAN alone.
www.asus.com/us/support/faq/1001005/
I have had issues where wifi restricts and holds a certain amount of bandwidth -it is a strange issue nonetheless.

do a factory reset. That will reset your routers password to the factory defaults.

you may need to re-boot your modem as well.

Why do you have to make sense?! Ugh, I guess I have to, I'm just worried I will somehow mess it up and end up without Internet (and I'm unemployed, so I need Internet like most people need hydration). If you think I'm overreacting with my fear of tech you should know I, among other things, actually managed to break a CD in my computer once - I can manage to fail anything.