Nothing wrong with toys, they’re meant to be played with.
If you deployed this to production though, the problem
is not that it’s a toy: its you not understanding what technical trade offs they are making to give you an easy environment.
I can tell you’re defensive though, might be good to learn what I mean instead of trying to ram a round peg into a square hole.
k3s is definitely fine to run in production, hence it's not a toy. You just have to understand the tradeoffs they've made, when you should change the defaults, and where it's a reasonable choice compared to other alternatives.
A toy implementation of Kubernetes would be something like a personal hobby project made for fun or to learn, that comes with critical bugs and drawbacks. That's not what k3s is.