Thank you! I had no idea. After I disabled background app refresh I installed a firewall (https://www.lifewire.com/why-you-need-a-firewall-app-for-your-iphone-

Thank you! I had no idea. After I disabled background app refresh I installed a firewall (https://www.lifewire.com/why-you-need-a-firewall-app-for-your-iphone-5080119 https://www.lifewire.com/why-you-need-a-firewall-app-for-you...) - in my case the open source, security audited, on-device-only firewall "Lockdown" see https://lockdownprivacy.com/ https://lockdownprivacy.com/