Well, one dirty way would be to cancel the label editing after it got active.
const eventBus = bpmnJS.get("eventBus");
const directEditing = bpmnJS.get("directEditing");
eventBus.on("create.end", 499, function (event) {
if (directEditing.isActive()) {
directEditing.cancel();
}
});
Cf. Sandbox.
A cleaner way that would need more work is to create a custom LabelEditingProvider to handle your use case.