The US is pretty punishment-heavy. As a non-US person it even looks sadistic. It's "now I got you, you son of a bitch" social game from "Games People Play".
Since you're against "punishment as a whole", I assume you by "punishment" mean "I want them to suffer for what they did"?
Giving more than (say) 20 years to most 20-year-old murderer is no different from 120, from either deterrence perspective. When they're 40 they'll be a different person. 120 years of terrible prison conditions does not make anyone better off, compared to 20. Except for the victim's "sense of justice". But man, 20 years? No year more than that will bring your loved one back.
Anyway, I agree that we need both types of deterrence for SBF. Otherwise what's to stop people counting on getting "only" 10 years. Steal a billion dollars, hide it in cryptocurrencies, and when you get out of prison you're older, sure, but you are super rich.
We need deterrence from him doing it again. And we need deterrence for everyone like him, and everyone who would be remotely involved him people like him. People need to know that if you help this kind of scam, there are dire consequences. Which is why his parents should face the full weight of the harm they caused, to show that it will all be taken away.
But I don't see that as "punishment". Not in the way I think you mean it.