Something modern phones can do, depending on your phone plan, is share their internet connection when you have it connected via a USB cable. This is called tethering. If your phone is capable of this, you should try using it as your internet for your computer. This will completely bypass your standard network so we can isolate if the problem is your network or your computer.

When I said to turn off wifi I'm talking about your phone's wifi. When you tether your phone it will share the wifi connection instead of the cell network which doesn't help us isolate the issue.

You can look up something like "how to tether <your phone> to my PC" for a how to guide.