Just going to say one thing, a point which a lot of people ignore or never mention, in order to drive an anti point.
While long-term inbreeding is definitely not good, but short-term inbreeding is actually beneficial (something people don't want to accept), and is a fact that many research have proven as well.
Which is why in many cultures, marriage between second-degree and further cousins have been legal for centuries.
The core concept behind it is that, just as if you keep inbreeding, your genes become weak and get damaged or destroyed and you lose out on immunity and other benefits.
If there is a lack of inbreeding, then the genes which are beneficial become weak and get destroyed as well.
Like, if a bloodline/gene say had an inherit immunity to some particular type of natural regional toxin.
But because of the outbreeding with others for many generations, that said immunity gets eventually lost after many generations (because of dilution of blood with those who didn't have such immunity), as there was no introduction of similar bloodline/gene to boost the strength of that particular positive gene.
From the research article i had read years back, it was said that, introduction of similar bloodline (aka., inbreeding) is necessary for every 5-6 generation of outbreeding, in order to allow positive genes to remain active and get passed down to later generations.