If you run a system that uses dracut to manage its initramfs, then https://github.com/gsauthof/dracut-sshd might be of use to you.
I have it setup on a server running Fedora and can’t complain. When the system reboots and plymouth shows the LUKS password prompt a ssh server is started in the background as well - so I can unlock the server either using keyboard or connect via SSH. When rebuilding the initramfs (eg. for a new kernel version) the ssh server is installed and setup automatically so I don’t really have to worry about anything after the initial setup.
In addition to drives being safer to replace and sell, encryption at rest should also protect against theft. So the scenario being someone taking the server or its drives. At least for me encrypting the drives gives a bit more peace of mind seeing as credentials for various accounts aren’t easily retrieved from the disks.
But yeah, this does not protect from data being read at runtime