Fylm Sl Aswd Mtrjm Anjlyzy -

Given the trouble, the most plausible intended plaintext might be — but that doesn’t match letter counts exactly (film=4, as=2, a=1, word=4, matrix=6, analysis=8) vs your string (4,2,4,5,7). So "mtrjm" (5 letters) could be "word?" w→m (shift -10?), o→t (-10?), etc. Not consistent.

f (6) → a (1) y (25) → t (20) l (12) → g (7) m (13) → h (8) → "agth"? no. Try shift 5 forward: fylm sl aswd mtrjm anjlyzy

f+5=k, y+5= d (25+5=30 mod26=4→d), l+5=q, m+5=r → "kdqr" — no. Given the trouble, the most plausible intended plaintext

Most likely: It’s a (each letter moved 5 steps earlier in alphabet): Given the trouble

Alternatively — it could be ? Try swapping adjacent letters in "fylm" → yflm? No.