That's pure and utter crap. If so, every third unit worldwide would be defective. My Switch I currently use is the second one, the first was replaced by Nintendo. Both units usually had 1 bar of WiFi Signal, the worst of any device I own. A few weeks back I received a new Router, after installing it, my Switch WiFi Signal went up to 2 bars. Since the new Switch Update it went up to 3 bars. Usually pending from 2-3 bars. I can download with full speed now and play without any lags
Connection Errors were always a problem with Nintendo devices, starting with the 3DS and Mario Kart 7 and Animal Crossing New Leaf. No matter how good your connection is, you will receive these Errors. And the main problem is simple, another Console is the host. Nintendos Online System is unique. As an example, the Mario Kart 8 Server is choosing a host, the connection for everyone playing in this session will be interrupted if this person has connection issuses. That's the system they use for Animal Crossing, Mario Kart and Splatoon.
Normally, a separate Server handles the whole matchmaking. If Nintendo will start their paid service, this should be the standard. But we all know Big N too well. If they could save money, nothing will change.