I very often use my cellphone as a tether. It works pretty well. Yours probably has that option, so I don't see any reason that you should buy an extra device that does the same thing, especially if you are planning to get a long cable soon enough anyway.
EDIT: I think I misunderstood. I haven't had a desktop in years. I guess they don't come with the ability to detect wifi still?
USB is okay, but depending on how far you are from the router a usb might not cut it and you might need to get a pcie card. This is more true if your internet connection allows for dual bands (2.4 and 5) and you want to connect to the better 5ghz band.
I've used both usb and pcie wifi adapters and the pcie ones have always been better in terms of reliability.
https://www.amazon.com/NETGEAR-Wi-Fi-Range-Extender-EX3700/dp/B00R92CL5E
Not quite a USB adapter, but I just plugged a range extender like that one and then it's just a short ethernet cable into my PC.
It's at the very least significantly faster than my WiFi speed.
Depends on what you're doing. If you're just browsing GameFAQs, that's more than enough. If you're trying to play online games, or stream 4k video, a USB receiver isn't going to cut the mustard.
