Alternatively, maybe the entire phrase is a riddle or code. For example, the numbers might correspond to letters in the name. Daphne has 6 letters: D, A, P, H, N, E. D is the 4th letter, so D5 would be E (since 5th letter). But it's D52. 5th letter of Daphne D52: DAPHNE is letters D A P H N E. So 5th letter is N. 2nd letter is A. So N and A? Maybe N5A? Not sure. Or maybe D52 refers to the 5th and 2nd letters of Daphne. 5th is N, 2nd is A → N and A. Then "Dad" could be adding to that. N, A, Dad? Maybe NADAD? Doesn't make sense.
Y (25) -16 = 9 (I) V (22) -16 = 6 (F) M (13) -16 = (13-16) = -3 → 26-3=23 → W. Hmm, "IFW"? Doesn't make sense. Yvm Daphne D52 Dad
Alternatively, the entire phrase "Yvm Daphne D52 Dad" is a cipher where each part is encoded differently. Let's take each word. Yvm → Atbash = BEN. Daphne → maybe another cipher. If Daphne is encoded with another cipher, but let's see. If Daphne is transformed into another name. If we take each letter of Daphne and shift them by some number. For example, shifting each letter by -1: D→C, A→Z, P→O, H→G, N→M, E→D → CZOGMD. Doesn't help. Maybe shift by +1: D→E, A→B, P→Q, H→I, N→O, E→F → EBQIOF. Still no. Maybe shifting by another number. Alternatively, maybe the entire phrase is a riddle or code