Does Aftera stop pregnancy two days before ovulation?

It might. There are no guarantees.

If you're relying on an app to predict ovulation, they're just a guide, so you may be closer to ovulation, or further away, than it suggests.

Ella (Ulipristal Acetate) is the only emergency contraceptive pill proven can prevent pregnancy during the 24 hours around ovulation itself (you can see that on the Manufacturer's website), but even that is not guaranteed to prevent pregnancy. Aftera (levonorgestrel) might, but it has not been proven.
In the situation where you're in your fertile days, you may want to use the Ella pill, instead.

If you want an additional/alternative method of emergency contraception, you can have an IUD fitted by a doctor within 5 days/120 hours of the unprotected sex. That may prevent a pregnancy from implanting. However, IUDs can sometimes be painful for women who've not given birth before.