Consider restricting themes and plugin editor from Admin Panel to prevent hackers who break into your website to distribute malware or conduct DDOS.
Try using wireshark to analyse your network traffic, you will be surprised to see many IPv6 traffic that you are not expecting in your IPv4 based network. These IPv6 packets are actually consuming your server and network resources for no use.
This article explains how to disable IPv6 in the network interface cards of Linux/CentOS servers.
Without using any external WordPress plugin, you can still disable Gutenberg with these codes in functions.php
Here is how to add a checkbox option to every new post of whether or not to email the post to Jetpack subscribers. Use the following code.