Atbash: a↔z, b↔y, c↔x, etc. t ↔ g h ↔ s m ↔ n y ↔ b l ↔ o So “thmyl” = “gsnbo” — but that doesn’t read as “simple”.
Given the pattern, this might be a (each key moved one to the left on QWERTY): thmyl brnamj ymn atsh ar
Yes — “thmyl” Atbash gives “gsnbo” — unless we shift the result. But known puzzle answers confirm: = simple cipher for this text Atbash: a↔z, b↔y, c↔x, etc