Can not reset iPhone 5C to remove my info to decommission

So I was using my daughter's old iPhone 5C mainly to access icloud and find my iphone and it worked fine on wifi. I upgraded my daugter's phone last night and was able to set up her old iPhone 11 for this same purpose. Then I tried to reset and erase the 5C as it is no longer needed BUT...it will not reset. Reset all teases me by running only to have phone boot up exactly the same. Erase all content and data asked for my apple id log in but when I try to log in it says verifcation failed. It will not do many things without wifi But when I try to connect to wifi, it just says cannot connect to my wifi. I have many devices connected to my wifi, the iphone 11 is connected to my wifi. My wifi is fine and working. I tried all troubleshooting recommended online and found no way to get wifi to connect even reseting the network settings. How do I get rid of this iPhone and remove my private info already on it?