Here's my Kubernetes theory:

This software is great for cases where the business need demands maximum usage of available hardware resources (turn all your compute into one pool, because your company is too poor to accept that not every CPU needs to be maximized 24/7) and also provides a foundation for high availability, automatic failover, etc.

Most businesses do not need this. They don't need nine 9's of uptime. Neither do you. You could absolutely survive with short monthly or quarterly maintenance windows (except when a security update demands immediate attention).

Is having your "infrastructure as code" useful? Absolutely!

Does 100% of it need to be IaC? No.

Does the complexity of having 100% IaC and reproducible make it worth it? Not even close.

Unless you want your ops team to be disposable. If it's all IaC, you can replace everyone with juniors who only know e.g., Terraform. They don't have to have any real skills beyond that.