During the Battle for Odesa and the following occupation by the Axis forces many records were lost. My grandmother on my dad's side grew up during the occupation. Thankfully my mom's side evacuated (Jewish) potentially due to my maternal great grandmother having been part of the defense as a field doctor and was helped organize trains of wounded and evacuees. She received medals for her efforts including Order of the Red Star. She was able to get on the last ship to leave. After the war she counted 28 relatives lost due to war or holocaust.
Some decades later her nephew made a booklet about the widely extended family tree despite spotty records at best. I know it took many years of research on his part, I should ask where our copy is.
That maybe took a dark turn at some point - but I was thinking primarily about how armed conflict has the potential to erase history.
One notable exception was a cache of church records found in a church basement in Germany a little while back. Sixteenth to 19th century I think. Can't recall if they are Catholic or Lutheran.
They were quickly translated and put online. They included my uncle's line; the details and quality were kind of amazing.
If feels like we of European descent have all of the genealogical advantages. For most other folks, gleaning their family data seems to vary between brutal and impossible.