Yes! It is possible to install Cerberus as a system app. (Even if it's rooted with Magisk)
Yes, Cerberus will survive a factory reset. And your device will be traceable after a factory reset.
Obviously the device will not be tracked if the system partition is deleted. Tested only on my Xiaomi Mi A3, Android 9 (Pie).
IMPORTANT: Before starting the procedure it is crucial that you open the Magisk Manager, go to the Magisk settings and activate the option "Magisk Core Only Mode", then restart the device. (This step allows you to write to the /System partition.
After completing all 8 steps below, you can disable this option and enjoy your modules normally;
NOW FOLLOW THE STEPS:
1. Download the RS File Manager app (To get root access, you must buy the premium version, so buy!); Alternatively, you can try the procedure with some other root file manager, I don't know if you will succeed;
2. Open the RS File Manager and find the option Root explorer. Tap on it and select Mount R/W;
3. Download the Cerberus app (Disguised version), after all you don't want the Cerberus app to be recognized by others, am I right?)
4. In RS File Manager navigate to the /System/priv-app folder and create a folder called Cerberus;
5. Now just paste the APK you downloaded in the Cerberus folder that you created;
6. Within the Cerberus folder, hold your finger on the APK file, then select more -> properties -> change permissions. Now change the permissions to rw- r-- r-- (I will attach a screenshot to help them);
7. Go to /data/dalvik-cache/ and delete all the content inside the dalvik-cache folder. DO NOT DELETE THE DALVIK-CACHE FOLDER.
8. Reboot your device;
After the device restarts, Cerberus will already be on your list of apps;