"I messed up" would be one example of a less distracting way to convey the same point. Persuasive writing, which SBF presumably desires to employ in this document, should never distract the reader from its thesis and ultimately its call to action.

SBF wants to persuade the reader of his thesis, which appears to be that he was acting in good faith and continues to advocate for his customers who are being materially harmed by the obstruction of the chapter 11 team. And his call to action is for his readers to help him resolve his disputes with the chapter 11 team.

Considering these goals, not only is opening with "I fucked up" a counterproductive phrase and a wasted opportunity for a more effective opening, but the rest of his testimony is even less persuasive on its merits alone. I'm not sure he advanced his progress toward either of those goals with his testimony.

But I do think he will find sympathy from some libertarian crypto advocates (at least those who can get past their suspicions that SBF is controlled opposition from a cabal of corrupt bureaucrats intent on regulating exchanges and introducing central bank digital currencies).