This thread is about using multi-machine clusters, and sqlite cannot be used for multi-machine clusters in k3s. etcd is the default when starting k3s in cluster mode [1].
No, this thread is about multiple containers across machines. What you describe is multi-master for the server. You can run multple agents across serveral nodes therefore clustering the container workload across multiple container hosting servers. Multi-master is something different.
The very first paragraph of the first comment you replied to is about multi-master HA. The second sentence in that comment is about “every machine is equal”. k3s with sqlite is awesome, but it cannot do that.
"Lightweight datastore based on sqlite3 as the default storage backend. etcd3, MySQL, and Postgres are also available."
[1]https://docs.k3s.io/