I want to change the name of anti theft in stealth mode. Is reinstall only way?

I want to rename the masked name of the anti-theft, since I chose a name that doesn’t match up with the gear icon and seems mismatched, which could lead to suspicion if a thief looks at my phone’s admin list.

Can I rename it without having to uninstall and reinstall anti theft?

No you have to reinstall its not possible in Android to change the app name without loading a new package.