Hi @Niels,
Thanks for your organized and detailed response! You should have seen a special solo screen for risk consent acceptance when you start up SonarQube again. Developer and higher editions will see a different UX for plugin acceptance, i.e. there is no checkbox on the Marketplace screen.
In any case, workaround #2 is actually the correct method, as explained now in SONAR-15687:
Users who want to use 3rd party plugins are advised to enable persistence, to ensure the continuous existing of their plugins after a pod kill and increase the tolerance for the startup and liveness probes.