Plenty of people use k8s or k3s for self hosting. But for most, the added complexity doesn't buy enough for the trade-off to be worth it. Keep in mind most people have a single node, so docker does everything they need.
Personally, even with a 4 node setup (of tiny desktops; the hardware you have would easily cost me $200/mo in power bills), I use docker swarm. Old and unloved, but does everything I need for multi node deployment and orchestration with only a sliver more complexity than vanilla docker.
Yeah don't ask me about my power bill, It's definitely in the vanity realm. I have cheap power where I live so it's not anywhere near $200. Still too high though. One day I'll get solar to offset it.
Personally, even with a 4 node setup (of tiny desktops; the hardware you have would easily cost me $200/mo in power bills), I use docker swarm. Old and unloved, but does everything I need for multi node deployment and orchestration with only a sliver more complexity than vanilla docker.