I tested my WIFI Speed and I am getting less than I am paying for

🤔 Well this is the laptop I have. I'm not sure how old it is, but I bought it at least five years ago.

https://support.hp.com/us-en/document/c04754284 

I don’t think anyone guarantees anything on wi-fi – too many environmental variables.  For example, in my home, I can see about 5 2.4Ghz networks and 2 5GHz networks (and one of each of those is my own.)  However, I have visited apartments where I can see more than 20!

5GHz will probably help if the problem is too much wi-fi use. (neighbors.)    It won't help if the problem is too many walls or too much distance. I've heard some bad things about the performance of USB wi-fi adapters too, but I suppose it depends one which one you get.

It could be anything including your device. How new/old if your machine? Yes. 5GHz adapter will help

https://speedtest.xfinity.com/devicespeeds

🤔 Well my laptop is no more than 20-30 feet away from the modem. Is that too far away for 5ghz? I've been thinking of setting up additional access points throughout the house using the AP below along with this WIFI USB Adapter. What about these devices?

TP-Link | AC1900 High Gain Dual Band 

Ubiquiti UniFi AP AC PRO 802.11ac 

When you say "With ethernet, I get 360 mbps", I assume you mean on a different computer - right?  Because the specs for that laptop say:  "Integrated 10/100 BASE-T Ethernet LAN".  So I wouldn't expect it to be able to get anywhere near 360 mbps even on a wired connection.

🤔 Right, I have a desktop computer as well. On that computer I get 360 mbps using an ethernet cable, Cat 6A. On the laptop though, its not getting anywhere near that high, 25 mbps max with WIFI.  

🤔 Well, we're only using the modem Comcast gave us, the 'xFi Advanced Gateway'. Nothing else in between our computers, no routers, extenders, etc. That's why I've been considering setting up additional access points along with a WIFI USB adapter. I'm going to assume that my laptop is fairly old since I can't use the 5 ghz band, even though I techinically should be able to since its got 802.11N standard. 

🤔 Well extenders are well known to degrade the signal by quite a bit. But access points? I don't know about that. It depends on how they are set up and whether or not you are referring to layer 3 wireless access points which are basically routers, or just layer 2 access points. With the latter, the coverage should be just fine since I'd set it up like my school has theirs set up, or like they are typically set up in enterprise environments. At my school, they don't have it set up as a mesh, they just use the roaming method, connected strategically throughout to cover as many of the dead zones as possible.

All of their access points behave like layer 2 translating bridges, meaning they are connected via ethernet cables to routers (some to each other as well I recall), and those routers are connected via ethernet to the modem which ensures the signal strenth is maintaiend across the board. In other words, it translates 802.11 WIFI frames into 802.3 ethernet frames. It worked very well when I used their WIFI at the school, so it should definitely work for me. Its not the most practical method to increase the signal since it requires lots of wiring and maybe even switches, but its also the most reliable, which is why its set up that way in enterprise environments.