with 1 week of prep and the ability to get any resources he can, DOOM wins easily. The resource part ensures his victory, specially when you start thinking about his recent relationship with FF. Even if Reed doesn't want to give Doom some resources or items, he could easily have Valeria help him get something from the FF inventory. Last I remember the FF still had ultimate nulifier, and an infinity gem. It's not even beyond reason that he would be able to get/steal all of the infinity gems from the Illuminati with 1 week of prep.
Any advantages that Doomsday has in regards to strength, speed and invulnerability is completely overshadowed with the extend of resources available to doom with 1 week of prep.