In the Documentation (1), we explain that the downgrade can be possible by applying the yaml files as the primary method of installing AMQ Streams / Strimzi.

We should consider the deployment using OLM, that does not support the downgrade scenario.

We should explain as well that using the yaml files method will broke the subscription and we are no more managed by OLM.

(1) https://access.redhat.com/documentation/en-us/red_hat_amq/2021.q3/html/deploying_and_upgrading_amq_streams_on_openshift/assembly-downgrade-str#proc-downgrade-cluster-operator-str