But even if you use the HP filter, AR still removes these highest frequencies! It actually has nothing to do with the filter. The resonant peak filter @ max cutoff is a hack to boost those recover those frequencies that are removed in the AR.
I determined this by loading the same 16-bit samples into: ( a ) Octatrack, ( b ) Bitwig, ( c ) Rytm and comparing in a frequency analysis plugin. Even with the HP filter, Rytm lost some energy in the highest frequencies, but you can “regain” them with the peak filter.