Why frequent WiFi disconnection error unable to join network

I could not connect to ANY wifi network on my iphone 13. Suddenly it stopped working on whatsapp, while all other devices at my office were fine. I did every imaginable fix over the internet. Nothing worked. Out of pure instinct and logic, I finally figured it out. I had installed Windscribe, a VPN, yesterday. That was the conflicting app. I uninstalled Windscribe and everything went back to normal. Too bad I had uninstalled Whatsapp and now its taking forever to restore.