How would you know that?
Historical Sharpe ratios are not listed on C2, only current ones.
Usually, the highest Sharpe ratios on C2 are for new strategies (which then deteriorate), and I can assure you that you do not have the highest Sharpe ratio ever on C2. Just looking through the files on my computer (which doesn’t have much C2 data on it), the highest past Sharpe ratio on C2 that I found was 8.4. While that is somewhat higher than your score of 6.7, I doubt even that 8.4 score was “the highest ever for a C2 system since C2’s 2001 inception.”
So it would be better to say that you have the highest current Sharpe ratio.
Further, what little evidence we have here suggests that high Sharpe ratios are the third highest predictor of poor returns going forward. See the statistical analysis in this post: I just want to vent a little
In any event, keep up the good work.