So using a WiFi adapter instead of wiring into an extender ostensibly in the same location is unlikely to do anything for you without further modification.
I wasn't asking about moving anything nearer the hub, but rather if you can run a cable from the hub to somewhere nearer your client. Because you have options which I'll list in order of preference. I think only the first three will definitely see an improvement (first option being the best by a country mile), the fourth may work and is low risk to try and I hate the fifth, but some people get acceptable results.
1. Run an ethernet cable from your hub to your client. Go outside and back in if routing it inside is a problem.
2. Run a cable internally from your hub to somewhere closer to your current device. Put an access point on the end of the cable, add a WiFi adapter to your client and connect to the access point wirelessly.
3. Turn off WiFi on your hub, buy a wireless mesh system that also has ethernet sockets, dot them around your house and wire your client into the mesh point you put closest to it.
4. Put a WiFi adapter in your client and use your existing extender as it should be used. Place it half way between your hub and your client and hope the signal reach is improved resulting in better speeds.
5. Use powerline. Put one next to your hub, one next to your client and cable them in. Hope for the best.