This isn't Usain Bolt. This is normal people doing normal work with normal technical tools, and then somehow people keep claiming they must be some kind of world-class genius to have done it. Try it for yourself before you claim that you'd have to be a world-class peak performer to have installed and configured some simple daemons on a few linux servers.
I'll try to take a different approach here than I did in my other recent reply to you.
I hear that you're saying that there are possible configurations that are insecure, and that at least some care and attention needs to be invested to avoid problems. I agree. This isn't specific to Kubernetes, as you show in your second link. This can be a problem, and people have in fact suffered harm due to leaving their doors unlocked.
On the other hand, most important security doors in most professional environments are not left unlocked and unmonitored.
If you have already learned basic sysadmin fundamentals, then you have the skills needed to learn to deploy and use Kubernetes just as securely as any other network service. The way that you learn to apply your general sysadmin skills to Kubernetes is by practicing with it. You can supplement your practice with books and training if you really want to, but it's not necessary. If you happen to have other people who have already gone through this process as support, that can help quite a bit. If there are any other better ways that people learn things like this, I have yet to hear of them.
If you don't already have those skills, then the way to build and develop them is exactly the same process. You try stuff out, read some docs, poke at things to see if you can break them. You can supplement this with classes if you like, but they're not necessary. Peers and mentors are great if you have them, but they're not necessary.
What alternative do you have in mind? What about kubernetes specifically is so monstrously complex? People keep asserting this, but I learned it just fine like any other nontrivial software I've ever worked with professionally. My peers at work learned it just fine like any other software we've worked with. My friends and colleagues I keep in touch with from previous jobs have learned it fine.
I don't really understand what kind of complexity bar you're trying to imply is just objectively too high to be reasonable? Yeah, it's got more moving parts than like Redis, because it does way more than Redis does. Sed is simpler than python, but that doesn't mean that you need to be Usain Bolt to learn python.
I bet you could get microk8s running correctly on your first try. Give it a shot! Here's a doc: https://microk8s.io/docs/getting-started
You could probably get some additional nodes in your cluster on your first try too: https://microk8s.io/docs/clustering
This isn't Usain Bolt. This is normal people doing normal work with normal technical tools, and then somehow people keep claiming they must be some kind of world-class genius to have done it. Try it for yourself before you claim that you'd have to be a world-class peak performer to have installed and configured some simple daemons on a few linux servers.