This is not true. Modern OS (at least on Android 6+) let's you select individual permissions for each app you have. So you don't allow apps that you don't rely. Why install fishy apps in the first place. Use your smart devices smartly. Equip it with an anti-virus. And always connect through a reliable VPN when you are on unsecured connections. This is what I normally practice.
Here are some more tips on securing your smart devices if you need em: https://www.purevpn.com/blog/understanding-smart-devices-security-risks/