You arent' forced to use service mesh and complex secrets management schemes. If you add them to the cluster is because you value what they offer you. It's the same thing as kubernetes itself - I'm not sure what people are complaining about, if you don't need what kubernetes offers, just don't use it.

Go back to good ol' corsync/pacemaker clusters with XML and custom scripts to migrate IPs and set up firewall rules (and if you have someone writing them for you, why don't you have people managing your k8s clusters?).

Or buy something from a cloud provider that "just works" and eventually go down in flames with their indian call centers doing their best but with limited access to engineering to understand why service X is misbehaving for you and trashing your customer's data. It's trade-offs all the way.