The amount of power that you are taking from Sonic is insane. Way underpowered. Also you can put speed steal because it wouldn't work. Time for me to prove y'all wrong, starting with how Wally having speed steal won't matter anyways as long as Sonic would be in Ultra form, or maybe in base.
Explanation:
Firstly we need to know how speed steal works. It doesn't just take the concept of speed from anyone. It takes their kinetic energy. There are 3 ways that I will explain that will make it not work. Kinetic energy is converted by potential energy, which we know Sonic has infinite (if I am wrong read the next paragraph, and potential energy aka stored energy includes the chaos energy stored within him, so like chaos control.) So even if he took the speed from Sonic, he would just have to take more energy. But can Wally even take that much? Wally West may be an omega hero but he cannot take infinite energy. Such amounts of energy would be too much. It's like when you over charge a battery. Too much and le kaboom. Also if you say Wally has infinite energy, it also wouldn't work. Can't take infinite from something. And Infinite + infinite doesn't really exist.
BUT WAIT you say. SONIC DOESNT HAVE INFINITE ENERGY you yell at me. Well I don't know if he does or doesn't, but guess what. DOESNT MATTER AHAHAHAHA. Speed steal allows the user to enhance their own movements by compounding the stolen kinetic energy with their own. The problem with that is that Chaos Control can also has an ability to reshape matter. This is especially easy for Sonic. Wally can control the kinetic energy of anything he touches, but Sonic is able to put a block on that due to freely changing the molecules of anything, including energy conversion. Wally’s speed steal would have no effect.
That should be it. Now I'm gonna read what other reasons y'all have for flash winning.