VPN app cripples phone

I had your VPN app running on my iPhone 13. Starting from November 1st, there were extreme problems with the phone regarding internet access. Nothing worked anymore. It took 10 days for me to figure out that the problem was caused by The VPN App. Simply turning off the VPN connections had no effect. Only the uninstallation of the app achieved the desired effect. Now I actually don’t want to install the app anymore. Security aside, this should not go so far that the phone is practically crippled by a secuity App. Does somebody has the same experince?.