Hate to say it but systemd, the init system of most Linux distros, already has PRs with maintainer backing to implement DoB recording.

Some people can't kneel fast enough.

I imagine people behind this law are pretty interested in this small but powerful user base. I would just boldly assume that a lot of people responsible for independent software and privacy advocates are using Linux etc. So its a interesting user base for sure. But regulating open source software luckily is pretty much impossible and they wont give up their(our) privacy without a fight. Also, we will see how much the user base will grow when these regulations get tighter.

They can simply say on their download pages that residents of Brazil and California are not allowed to use their OS.

Motorola* bending the knee to the mass surveillance corps and international governments comes to mind. We'll see how their deal with GrapheneOS goes now.

Big name for government backed hacking tools to list them separately on supported devices / OS cause it's more secure.

GrapheneOS has a deal with a hardware manufacturer, Motorola. I'd consider this refusal to be a big deal on those grounds alone

Frankly I think they are the largest os vendor that is going to take a principled stance on this.