First Bottlerocket is not Amazon Linux 2, it is its own minimal operating system, with most components built from the ground up in Rust. This is totally different than the Amazon Linux 2 you may be familiar with (and most other operating systems for that matter). Bottlerocket is optimized for running containers with high security isolation. The host OS is extremely minimal, it does not come with bash, an interpreter, ssh, or anything beyond the system basics needed to run containers. In fact it uses an immutable root filesystem. You aren't intended to run or install things directly on the host at all.
Everything that is installed and runs on Bottlerocket runs as containers, which are kept isolated from each other and the host with best practice security features such as SELinux. For example you can connect to a container on the host via AWS Systems Manager, or you can optionally enable a container that lets you connect to it via SSH. Once again the thing you are connecting to is the container on the host though, not directly to the host.
For this initial release of Bottlerocket we are focusing on providing image variants that are prepackaged with the requirements to serve as underlying container hosts for an ECS or EKS cluster. However we also intend Bottlerocket to eventually be something that anyone can use, anywhere, even outside of AWS, if they wanted to benefit from the secure by default, container first design of Bottlerocket.
You can read more about the security features of Bottlerocket here: https://github.com/bottlerocket-os/bottlerocket/blob/develop...
And you can find a bit more of the charter / goals for the project here: https://github.com/bottlerocket-os/bottlerocket/blob/develop...