Order of letters by frequency
ietuasnmorcdlpqvbgfhxyz

K4 order of letters by frequency (- indicates similar frequency)
K, S-T-U, B-O-W, A-F-G-I, L-Q-R-Z, D-J-N-P, C-E-H-V-X, M-Y

So far…

Latin has no J, U, or W

OBKR
_OXOGH_LBSOLIFBB_FLRVQQPRNGKSSO
T_TQS_QSSEKZZ_AT_KL_DIA_INFBNYP
VTTMZFPK_GDKZXT_CDIGK_H_A_EKCAR

Kryptos Fan