If you were Google k8s wouldn't cut it. I have experience of both options in multiple projects. Managing containers yourself and the surrounding infrastructure vs. using k8s. k8s just works. It's a mature ecosystem. It's really not as hard as people make of it. Replicating all the functionality of k8s and the ecosystem yourself is a ton more work.

There are definitely wide swaths of applications that don't need container, don't need high availability, don't need load balancing, don't need monitoring, don't need any of this stuff or need some simpler subset. Then by all means don't k8s, don't use containers etc.