One of the unique features of MX has been the ability for the user to choose between systemd and sysVinit on installed systems. The magic sauce that made that work is a package called systemd-shim. However, development on systemd-shim stopped some time ago, and Debian recently dropped the package from the Buster repositories.
Our understanding is that the current state of systemd-shim does not work correctly with the version of systemd in Debian Buster, so we are exploring options for the future of MX.
To that end, one thing we want to explore is the possibility of continuing development of systemd-shim (and whatever systemd patches may be necessary for the systemd-shim to work properly). We have placed a BountySource job here: https://www.bountysource.com/issues/73421147-systemd-shim-removed-from-debian
So if you can help out with this project, please check out BountySource (FAQs) and let us know.