Algorithms of POS, POSa and POW are different, you can see details on wikipedia and some trusted sources, for now the level of security of transactions will be a long term problem for BSC, it may not be visible at this time, but when many projects use the BSC Ecosystem, there must be some congestion that occurs.
there are only 2 options, fast but vulnerable to attack (security) or blockchain with slightly slow transactions but with good security like ethereum.