I recently switched to bazzite. What i ended up doing was using bluebuild and making my own github repo. Which takes the newest version of bazzite upstream and strips out flatpaks i dont want or certain packages. And installs some i want. The documentation could use some work but its a great concept
And my repo if you need insperation and or help with configuring bluebuild feel free to ask!
Im still trying to figure out how to make it automatically take distrobox assemble distrobox.ini and setup my distroboxes
And to answer your question with bluebuild you can take bazzite-dx and set that as your image in recipe.yml and then specify what packages you want added via brew, flatpak, or rpm-ostree or removed