RedHat/IBM does have an Illinois presence so will likely be compelled to add it to their distro, and will likely do it through systemd. So to avoid it getting into any consumer distro you'd have to ship a patch to remove it from systemd.
This is probably all completely irrelevant to StageX since it's a distro designed to be used in containers, AFAICT.
I run stagex on servers and workstations baremetal, however admittedly minimal. It can run lots of ways.
IIRC systemd already started implementing some hooks for age verification API
Maintaining forks is pretty trivial now with AI.
Fortunately patching out such nonsense is as easy as running a few commands.
Project tracking these laws and providing patches as needed: https://agelesslinux.org/