As more people test, utilise and deploy Galera Manager, there is always room for support requests, and we see that at the Galera Manager Support Repository on Github. We encourage you to file requests, as they help with our roadmap as well!
We have had a feature request to be able to support Debian 11. The main stumbling block was that Galera Cluster didn’t have a Debian 11 release, but this has been fixed with our release of MySQL 8.0.26; one can expect this to be in a future release.
For the best experience, we recommend you to install Galera Manager on a clean host, i.e. not on a host with existing running software. As you may already know, there are requirements for storage as logs can get large, for example. However, we have received requests to run apache2 instead of nginx. We have now ensured that we check for ports that are available (and will report and error, then fail if the ports required are in use), and we also have instructions on how one can run Apache and a Dockerized Galera Manager.