Addition to my analysis:

1. e6!!! Qxd6, 2. Qe4! Kc7, 3. e7! Rb8 (preventing 4. Qb7+), 4. e8=N+! Rxe8, 5. Qxe8 and White wins!

1. e6!!!

a) 1...Qf2+, 2. Qxf2 gxf2+, 3. Kf1 Re8, 4. e7 and White wins

b1) 1...Qxd6, 2. Qe4!

b2) 2...Qe7, 3. Qa8+ Kc7, 4. Qb7+ Kd6 (4...Kd8, 5. Qb8#), 5. Qc6#

b3) 2...Kc7, 3. e7! Qxe7 (3...Re8, 4. Qb7#), 4. Qxe7+ White wins.

1. e6 Qxd6
2. Qe4 Kc7
3. e7 Rb8
4. e8=Q Rxe8
5. Qxe8

it's a winning position for white