Sigh... I already explained this... I believe thoroughly... right above your post. Here it goes again:
The Pixel 4a (which you don't actually use apparently... I guess your son does). The only thing that's necessary to disable the wifi on the 4a... with default settings... is to put it in your pocket. This is because of two features which may or may not be unique to the 4a (I've never had any other Pixel so I couldn't tell you about those):
"Tap to Wake" and "Lift to Wake".
Before creating a screen lock code the phone could be WIDE OPEN in my pocket. Calls... emails... you name it. "Tap to Wake" meant all it would have to do was tap ANY SURFACE of my pocket... and the phone would just unlock itself.
As I explained above... after creating a screen lock code... that would no longer happen... but the top menu could still be slid down and because the phone was just inputting random touches then "Yes":
EVERY SETTING ON THE PULLDOWN MENU COULD BE PRESSED.
(bold, all-caps, underlining might have been going to far... you get the idea...)
Obviously if I said it happened... it wasn't just for the entertainment value. IT HAPPENED.
I even found a solution which was to disable "Tap to Wake" and "Lift to Wake" in the Advanced Settings. Now it behaves like every other phone I've had in the past fifteen years.
Seriously... I don't understand what was so hard to believe...