For JDBC HA, we can have two Artemis crs in primary mode using the shared store to guard or lock activation. Both compete and the first in gets the lease lock and activates. The other waits to get the lock on release.
For not persistent deployments, there is no shared store to use as a lock. In kube we have etcd and in the same way that the operator can have a leader/follower activation using etcd as the coordination point, the broker can make use of the same mechanism.

The plug-able lockers may be a good entry point, or there may be a simpler activation gate. This needs to be researched. The java operator-sdk gives us an api to the etcd lock, the work is to find a good plugin point into the broker.

ShareStorePrimary, or just PeerPrimary or Primary with some lease lock is the simple pattern. And it can be independent of the storage or even the presence of storage (for non persistent use cases)