That`s why Czerny exercises and similars may be less useful... You may wish to choose another approach: do see where is your dificulty and direct your exercises in order to win that specific difficulty. If the difficulty lies in a weak finger, for example, work with this finger only, you see?
But we dont need very strong fingers, because "strong" is the enemy of "fast". May be, your problem lies in finger independence. If it`s the case, you may try a very easy exercise: hold down your five finger and then play 1-2, 1-2, 1-2.... 1-3, 1-3, 1-3... 1-4....1-5, 2-3, 2-4,2-5, 3-4..3-5... "ad nauseum".
If your problem is speed, use parallel sets (in the right top of this page, you may search many posts about parallel sets, ok?).
Best wishes.
Rui