Systemd-sysext Help Needed

I am running Bluefin immutable distro and I would like to test Niri. I found on the net that the cleanest way is to use systemd-sysext and I have managed to install Niri using the community extensions.

Now I would like to install Dank Material Shell, and it has a couple of pre-requisites and I am clueless how I can add them again with systemd-sysext.

I tried to look for additional information, but found very little on the matter. Do any of you have experience with this?