The only thing I can contribute to this thread is the following question (for PoSers):

How does PoS support chain splits?

The ability to fork the chain is fundamental for resilience.

Without this, you might as well just have an Excel spreadsheet on somebody's laptop IMO.

To my understanding, in a PoS chain, both forks of a chain retain the staking balances on both sides, and it would only make sense for the stakers to validate the same blocks on both chains.
This would end with two chains with the same parameters, which defeats the point of a split.

In a PoW chain, whenever a chain split occurs, miners have to pick which fork to mine on, so you would be left with two competing chains of different parameters, of which one would eventually win out as the coins on one chain slowly devalue relative to the other as people sell their coins on one chain to buy coins on the other (as it should be).

Am I wrong? Is there some mechanism by which PoS supports chain splits in a robust way?