Security is something that can be improved infinitely. Managed Hosting Intense addon setups the basic security features, however, there is can be something needed to be adjusted as per the server function. What attacks are you worried about?
As for the Brute Force warning, if you received it, this means that the IP address attempting to brute force SSH access to your server was already blocked by BFD installed with the Managed Intense addon and you shouldn't be worry about it. It was just a notification.
Please advise if you have any additional questions and we will be happy to assist you.