iPhone 11 will not stay connected to WiFi

I have spent to much money to have WiFi issues. What can I do to fix the iPhone WiFi issue. Please do no give me the same generic answer that I see on every question that has the same problem I am having I have tried resetting my router resetting my phone resetting my network settings I have tried everything and I am still having issues with my iPhone not staying connected to the Wi-Fi I am starting to feel like this is a issue created to cause customers to pay overage fees when we do not realize our phone is in cellular mode when it should be connected to the Wi-Fi I have spoken to several other iPhone users and they are experiencing the same issues we are seriously contemplating looking into Taking legal action because we cannot get adequate support through Apple all I want is to be able to use Wi-Fi on this super expensive phone that I am paying for