Many distributions have decided not to comply. Debian has settled on not making anything like this mandatory, as they are an international project, although they may (after discussion and likely voting) agree to optionally package age verification stuff for users who want it for some reason.
I'm worried that Poettering's new startup is designed to ban unapproved Linux, BSDs, etc.
https://linuxiac.com/systemd-creator-lennart-poettering-join...
The cynic in me says the Win 11 "you must have a TPM" push (along with passkey's "big tech owns all your accounts" design) were rammed through specifically to centralize control of the open web.
At this point, if the federal government actually forced OS-level censorship, most literate folks would just download Linux. So, first, they need to close the remaining door.
I'm not exactly holding a candle for debian. SystemD has already started adding support for this, and, in the past, downstream has been able to force unpopular debian votes through.