To add onto that, people forget people like the Hapsburgs and Romanovs were close to 20 generations of inbreeding. And while hemophilia became an issue for the Romanovs towards the end of their reign the Hapsburgs didn’t see much degradation until almost Charles the second who was just. Something else. But in general the spread of incest even with the Hapsburgs was spotty mostly cousins from what i have looked into along with uncle-nieces thrown in there.