My RedMi phone is facing lots of problems!
You can set restrict data usage on Xiaomi phones. Go to Security -&gt; Data Usage -&gt; Restrict Data Usage. There you can see 'Installed' and 'System', which means installed apps(user apps) and system apps. You can uncheck both data and wifi for the apps , which you don't need to connect internet.
Note: Some system apps need data, so be careful on changing system apps.

The next thing is, you can set permissions for each apps. Go to `Security -&gt; Permissions -&gt; Permissions. Click on each app and set permission for each as you wish(Location, call log, contacts etc).

You can also set, auto start, which apps should start automatically after boot. Security -&gt; Permissions -&gt; Autostart