Same issue here. It was fixed for a couple of weeks until the latest 14.5 update some days ago which happened automatically over a night. Now I am facing the same frustrating issue every hour or so. And not only that I also have unexpected restarts. Apple devs for the love of god this is a basic function. We all have payed so much money for your devices. Respect your clients or you will lose them eventually. Do something and fix this damn thing.

The problem is that sometimes the wifi can't be "toggled". Even with the aformentioned solution, my iphone wont always find the wifi and then I have to reboot it. So no that's not the entire solution to the problem.

My ios 14 problem doesnt revolve around only toggling wifi on and off. Sometimes the wifi cannot be toggled as I said. It is completely grayed out and cannot be selected. Then I have to restart my phone numerous times and if I am lucky the wifi will be fine for a while. Now this doesnt happen with an old iphone that I have which still carries an ios 12 or sth. I have already tried everything including your solution and it simply didnt work. So there is more to that. I expect from more people here to try it out and tell us what they discovered.