For those like me who are a great deal fainter of heart than the author, there's always k3s [1] (installed e.g. via k3sup [2]) to take care of the "hard" Kubernetes part, at least until something breaks, though I've been lucky so far. Will run great on a Pi 4 and decently well on a 3/3+. The only big issue I've had so far was finding 32-bit armv7 images (I'm running Raspbian; I hear Ubuntu can do 64bit just fine), most projects only ever publish arm64 ones.
[1] https://k3s.io/
[2] https://github.com/alexellis/k3sup