Assuming there aren’t any particular scaling or performance requirements, if I were managing something like that, I would almost certainly not use k8s. Maybe systemd on a big box for the services?
I agree with you and I'm always confused when people talk about process isolation as a primary requirement for a collection of small internal services with negligible load.
In addition the overhead and reporting drawbacks of running multiple isolated databases is vastly higher than any advantaged gained from small isolated deployments.
