To expand on Vandril's explanation.

i80 Bodies have a max of 21 for Determination and 30 for all other secondary stats.

A Monk wearing following body pieces would get the following secondary stat bonuses in Frontlines and i80 sync:
  • Warwolf Corslet of Striking (i70+10 Morale): Det +15, Crit +30
  • Fuma Koromo (i80): Det +21, Crit +21
  • Shirt of The Divine Hero (i80): Det +15, Acc +30
  • (Augmented) Shirt of Striking HQ (i90): Det +21, Crit +24
  • Weathered Gloam Tabard (i100): Det +19, Crit +30
  • The Guardian's Breastplate of Striking (i100): Det +19, Acc +30
  • Gloam Tabard (i110): Det +20, Crit +30
  • Hawkliege Cyclas (i110): Det +21, SkSp +29
  • (Augmented) Ironworks Cuirass (i120 or i130): Det +21, Crit +30