You must submit your original birth certificate, so unless that has the name that you want to apply with you'll have to explain the difference and you will not be able to hide it (I'm assuming also accompanied with the legal documents that prove the name change).

so in theory if i manage to get it fixed, im good? Do you know what other documents germany requires? Also there is a requirement to not be a criminal (duh). How is this confirmed? i assume they contact the country of origin to check but what do they actually ask and from who?

Thank you for answering btw!

That however does not mean that your name will be in your official documents etc. And will probably only come up during the application process.

of course it will be, theres no way germany wont record that information and keep it forever. if some government official looks me up for any reason, or police for any reason, im willing to bet it will show up.