As far as I can tell, once some blockchain data is fed into a hash, this creates an epoch nonce that is used to define the slot leaders in that epoch.
How is the nonce used to select slot leaders, and what is slot leadership evaluated against to deliver a block on average every 20 slots? Why can some slot leaders create a block, and why cant others?
Are inputs like transaction hashes part of the block proposal and acceptance process? Is there some kind of difficulty/target like in regular PoS?