nothing in upstream will force some type of age verification in Qubes OS, at most upstream will add further optional parental controls that have no purpose in Qubes OS, given it is a single-user-as-admin OS.
so if you look at what the systemd merge actually is:
you see it is adding birthDate to an existing JSON userdb that already stores emailAddress, realName, location. so Qubes OS is already tracking your email address, real name, location?? no because those are not actually asked of the user or used by Qubes OS.
for the birthDate only admin will be able to change it, which in Qubes OS is the user as the user is admin…
so what are they going to do, force us to change the architecture of the OS away from single-user? and if we ignore them? will some random US state become the first place in the world to block residents from accessing Qubes OS website & downloading ISOs? what about all the ISO mirrors hosted elsewhere? etc etc.
basically these states are setting themselves up to be embarrassed (in court, in media, in public opinion), i dont think it will hold up to legal scrutiny, and regardless it shouldn’t affect Qubes OS users.
& we will continue to keep an eye on upstream in the meantime, as we always do.