What Usually Goes Wrong
The common outcomes are dull: heavy advertising, notifications pushing deposits, a package that reinstalls itself after removal, and device data sold onward. The severe outcomes involve accessibility access — messages read, one-time codes forwarded, taps performed in other apps. Very little of it is visible while it happens, which is why the permission list read beforehand is worth more than any amount of vigilance after.
It is also worth saying that plenty of operator apps are entirely ordinary software with a short permission list and no surprises. The checklist is not an accusation; it is the thing that separates those from the ones wearing their branding.
If Something Is Already Installed
Revoke accessibility and device-admin access before uninstalling, since some packages resist removal while those are active. Then remove the app through settings, then change passwords for anything sensitive from a different device. Order matters more than speed.
Why a browser avoids this entire category is covered on the browser or app page, and the rest of the guides are indexed on the home page.