you will have a much easier time setting up database and networking, running backups, porting your infrastructure to other providers, and maintaining everything, than with legacy control panels or docker compose.

I really don't see this. Database? Same but needs a service. Networking? Services and namespaces instead of docker networks. Backups? Basically same as Docker but k8s has cronjobs so you can have it at the same place as your other stuff which is a good point. Porting infrastrutcture? Copy compose file, env files and volumes vs. copying all resources and pv.

I am absolutely not against self hosting in k8s and if IP already had k8s running, I'd recommend it too. But I don't see the benefits for the scenario op described.

You might be right with the better/more accessible docker docs everywhere being the main reason it's so popular, but it's also usually just one file that describes everything AND is usually the supported install method of many projects where helm charts are often third party and lack configurability.

CNPG is cool, but then OP also needs to learn about operators and custom resources :) More efficient? Yes. More complex? Also yes.

The biggest challenge for kubernetes is probably that the smaller applications don’t come with example configs for Kubernetes. I only see mastodon having one officially. Still, I’ve provided my config for Lemmy, and there are docker containers available for Friendica and mbin (though docker isn’t officially supported for these two). I’m happy to help give yaml examples for the installation of the applications.

As said above, I agree it's one challenge, but added complexity is not to underestimate.

Completely off topic: Your post did make me think about running my own cluster again though. I also work on k8s at my devops dayjob but with a cloud provider it's not the same than running your own ofc. I've also been thinking about tinkering with old smartphones in that potential cluster..