my wifi has stopped working all of a sudden FULLY

i use an iphone 7 plus and all of a sudden i recognised that my iphone 7 plus was no longer connected to my wifi. i tried disconnecting and reconnecting my wifi connection, rebooted my iphone, resetting my network settings, turning my router off and on again after a few minutes, and updating my iphone to the latest software IOS 15.3.1 with someone’s mobile data but nothing has seemed to change. i really don’t want the solution to be purchasing a newer model as i cannot afford it. my own data doesn’t work but my other devices are successfully connected and normal. even my old iphone 6s is connected to my wifi. other wifi connections don’t work with my iphone 7 plus.