Android 11 for note 9

if we root, will we get regular monthly security updates? what are the disadvantages of rooting?

Rooting can go wrong and turn your phone into a useless brick.

You will void your warranty.

Your phone is more vulnerable to malware and hacking.

Some rooting apps are malicious.

You might lose access to high security apps.

Some high-security apps check whether your device has been compromised by hackers before letting you use them. One example is Android Pay. If you don’t want to lose access to these apps, it’s probably best not to mess with rooting.