The Pi 4 is the first generation that's actually not horrible at running Kubernetes, so I'm mostly having fun with that (ongoing saga at www.pidramble.com).
One of the major issues I had was the master (control) node would start getting a little weird sometimes, and it was always due to memory pressure (even if not scheduling pods on the master Pi).
Kubernetes docs _say_ 1 GB is the minimum memory requirement, but 2 or 4 GB is more realistic, because at 1 GB and no swap you have precious little overhead.