PoW has nothing to do with blocksize.
Dude you really don't understand the math of propagation. That is an idiotic claim.
the propagation is a different matter that has nothing to do with PoW
validating transactions and making a hash, and transmitting a block to other nodes is the same if it was PoW or PoS
the actual work of PoW and PoS is a separate thing.
once PoW has a solution. the new hash is added to the block data. and funnily enough to check that the PoW solution (hash with so many 000 at the start) actually takes less milliseconds to verify than it does to chck signatures of 'stake' holders block header data.
again the Proof_of_..
and the tx data inside a block are 2 separate things