My pc randomly stopped connecting to my router. It was working fine for a long time. Signal strength is fine. It will sometimes connect but at a very slow speed <100kbps and eventually go to zero after a minute or so. My phone connects fine to the modem and my PC connects fine to my phone hotspot. Everything on my PC is up to date and I tried a factory reset on my router. Its just a cheap huawei router and tplink wifi dongle.
You have very few options. You could see if there was a different driver. It is not uncommon for windows to mess stuff up with their update. Try the driver directly from the manufacture. You could also try a older one to see if it is different
The best place to get drivers is the wifi chipset manufacture site. It should tell you the wifi chip that is being used in one of the driver menus.
After that you start to suspect a defective device. Although it is not real common the wifi radio chips do fail and you see issue like you report. It would be nice if it would just not power on at all rather than partially work when these fail.