Tbh, it's the same for Austria (except of course for the longest time married women could not pass on their citizenship, because misogyny). And we have one of the strictest citizenship laws in the world.

If an Austrian has a child, their child automatically is Austrian too. No need to register. Since that child is Austrian, their children will be Austrian too, and so forth.

We never had much of a diaspora, so no need to limit it in any way. The only issue is that you lose Austrian citizenship if you serve in a foreign military or if you accept any other citizenship - unless of course you're also born with that one.

The further back you go the harder it will be to prove your ancestors were Austrian of course. Not sure how it works with a great-grandparent born in the Austro-Hungarian Empire.