Remember the old Baldur's Gate days where your monk would gain Armor Class with levels ?
Now you can do the very same here in Deadfire.
Transcendent Suffering now provides +1 universal Armor Rating at level 1, with a further +1 bonus every 2 Power Levels hereafter.
I have not modded the inability for Monks to wear armor, whether you want to play your monk naked à la Baldur's Gate or not is your decision.
Mod over here :