Yes, you can't use an extension like this in Quarkus, but you can use an extension doing the same. You will find some code vetoing beans in the Quarkus codebase (in the reactive messaging extension we veto the metrics bean if metrics are disabled).
The attribute I was mentioning would be on the channel level, not attribute level. It would not be on the method but on the channel. Note that it would force you to disable the strict mode (disabled by default so just in case you enabled it) as your method would not be connected to a channel.
Clement