Not to my expectation, not on a sandbox for sure. Also, Mendix will have an extra hard time supporting the V4-cloud if they allow superuser-access for the database. Your best chance is purchasing a license and do an on-premise installation. If that is within your or your organization's reach, you best contact Mendix sales representatives and talk this through.
I would not really require the superuser permissions, I would like to have this extension enabled however.
I would assume that running Mendix on a Postgres database should make it possible to leverage the most on this database, even in the cloud, since most Cloud providers I have worked in the past with (Azure / Digital Ocean / AWS) all have extensions available for use that are even not bundled with a default Postgres installation.