Facing the same issue again.
Tried a 30.00 USB wireless and was getting about 1-2 mbps. Barely worked.
Access point is two:
one is in a office building 238 feet NE
the other is 330 feet in the same direction.
Another SE that is 508 feet away.
Both are xfinitywifi hotspots.
First step was to install a TP-Link 802.11AC Adapter
https://www.tp-link.com/us/products/details/cat-5519_Archer-T9E.html
Pointed the antennas the wrong way, and get under 7 mbps.
Point the right direction: 20-29 Mbps
Just downloaded the latest drivers so re-testing.: 20 using TP Link software.
Now going to reboot without it, and just use windows.