crazyivan u have a very good overview of dmd
just some little detail can lead to missunderstanding

example coins can act as masternode collateral or participate in pos
but same coins cant do both at same time

amd the pos in dmd v3 is not the same as the pos in dmd v2

the new pos will act like mining that mean
the blockreward is the same no matter who find the block
and more coins is like more hashrate
and provide a higher chance to find a block
there is no annual interest and no coin age that influence chance to find a block or the reward of the block

over all still the calculations we made show that a active pos wallet will very likely earn more via pos in dmd v3 compared to dmd v2