[trebb]

That’s the best bet - it’s not all that odd for a USB port to go bad - or have a “less than optimal” adapter for connectivity.
On my last computer, my Ethernet port went bad and I got a USB/Ethernet dongle which worked OK - but you would still need the cable for such so the built-in Ethernet port is the best option.
Doesn’t your current Win10 machine have WIFi built-in? Most do these days. If it does, it’s possible it’s just disabled and/or the adapter interferes with it.

[PROCON]

I have a refurbished Dell desktop, no built-in WiFi. Besides the ethernet cable, I also ordered a wifi adapter/dongle with an antenna too, just to experiment.

[PROCON]

I received my wifi adapter with single antenna today, (TP-Link USB Wifi Adapter for PC AC600Mbps Wireless Network Adapter for Desktop with 2.4GHz/5GHz High Gain Dual Band 5dBi Antenna, Supports Windows 10/), and it's working great, zero wifi drops at all today, finally!

If I don't have anymore problems, I won't even use an ethernet cable.

Thanks for all your help!