t (20) → G h (8) → S m (13) → N y (25) → B l (12) → O So thmyl → gsnbo — not clear.
Let’s test Atbash on the first word: thmyl → t(20) ↔ g(7), h(8) ↔ s(19), m(13) ↔ n(14), y(25) ↔ b(2), l(12) ↔ o(15) → gsnbo — not obviously English. thmyl brnamj strym snayb bbjy llandrwyd
Better approach: This might be from a game or challenge. The last word “llandrwyd” is close to real Welsh “Llandrwyd” (a village?). If we assume it’s the target, then the cipher might be reversing the alphabet (Atbash) but with Welsh spelling. Let’s try Atbash on whole phrase: t (20) → G h (8) → S