No, SBF did directly steal from FTX users. He used an intermediary (Alameda) to do so. The end result is the same: he stole from customers to enrich himself, his family and his friends.
I'm sure both SBF and Madoff originally thought they would be able to make enough money to cover up the theft.
From what I read Madoff didn't seem to, he never actually tried to invest the money and couldn't really have expected his ponzi scheme to become a permanent engine of the economy or anything..
I don't really think that has the moral conclusion people try to imply though. Thinking they could get away with it as a permanent secret gap that no one need ever know about is actually a worse moral character.
I'm sure both SBF and Madoff originally thought they would be able to make enough money to cover up the theft.