I think if you have data on the truck through the data plan - then you don't "need" wifi. So that could be how it pulled the OTA update.
To connect to WiFi - when you are near your home network - you will see the wifi logo (the fan) on the screen - and if it's not connected there will be an...
Tesla's have giant batteries compared to even the Powerboost - so the way From manages their connection is - connect, check for updates, send telemetry data, etc, then disconnect... No need to burn battery when there's nothing left for the vehicle to do.
Band steering (anyone's) sucks in general... So I'm not suprised... probally told the truck - hey - go to 5ghz for speed - and then the signal sucked... it hung... then flipped it back to 2.4 and since SYNC is about as robust as a flaccid banana at the network layer... that was that...
I had the same thing - my home network is fairly advanced - separate VLANS's for family, guest, IoT crap, secured VPN's for data work, etc.
My new 2022 F150 will connect to the WiFi network, register it's MAC and receive an IP address... and then just sit there - and then tell me on the screen...
It took all of 5 minutes. Simple and same wire color everyone here stated. Green is ground and black is positive.
easy peasy. On with key on. Off with key off.
Do it! ;)