They will be successful at forcing corporate operating systems like MacOS, Windows, and maybe RedHat, but they have no power to compel code being added to independent international volunteer maintained open source operating systems maintained.
For projects with no legal entity like Stagex, arch, alpine, etc... we do not have to comply and there is no legal mechanism that exists to make us. Who would you even target? All maintainers have equal power, and cannot make changes alone. Especially not changes we do not want, for free.
I think the legislators should PR age verification code to all open source operating systems on their own dime, so we can ridicule them mercilessly before closing them as WONTFIX.