1. Ross Ulbricht might just have transferred bitcoin from his wallet to another one.
The surprising thing is that while he was in prison, no one gave him such a large donation (if anyone did before). Therefore, your version has a right to exist.
2. Someone donated this much to him, but who could have be.
Satoshi...

But by accident mistakenly wrote extra zeros.

3. This was part of the share on the seized bitcoin transactions tagged under cannabis and narcotics platform he operates by the government.
Before that, let me also remind us of how Ross Ulbricht was pardoned by president Trump out of the prison, today we have this to also say concerning a $300,000,000 worth of bitcoin into his wallet, What do you think.
Maybe then it was Trump who made this donation? Again, having made a mistake with extra zeros.

The amount is really impressive to just give away, even for such a legendary person.
Also, if there are no investigations on this matter from government agencies (normally, they should have questions about the origin of this transaction), then it becomes clear who the probable donor could be.
But in general, maybe it's enough to count other people's
BTC? Better to be happy for the person whose life is gradually getting better. It seems to me that he deserves more than these 300
BTC (at least he could have saved much more to this day).