This is what I'm getting at. That is an enormous overkill for a single server, and exactly the problem with kubernetes: It drives so much complexity that you kind of need this type of heavy-duty enterprise grade solutions even in an area where you really shouldn't need it.
If it's just a single server, you're fine with logrotate and grep.
So first of all: I do have to clarify that I just use bare podman containers deployed by ansible and not a while k8s setup, so I'm defending containers and not k8s. But anyway:
Who said graylog is only logging on that single server? That server is by far the biggest and hence why I run multiple services with big dependencies on it, but I have that server, 2 cloud servers (one running my personal web page and other publically accessible services, one running a couple of game servers) + a couple of Raspberry Pis.
Even if I didn't have all that, a web interface to configure it to email on ssh login or send me a mobile notification that my offsite backups are still happening and/or not happening for devices or similar items would still be a nice feature, even if you personally feel it's too complex or you could write a cron job for each of them.
If it's just a single server, you're fine with logrotate and grep.