Alright , it is what it is. No one does 3ds repair around here, so searched around and waited for a long time. It was a bricked either way.
@vb_encryption_vb , I will take it to back to the shop again & see what he can do. You are right tho, I did learn soldering just two weeks ago, this seems advance.
I did use liquid flux, alchohal swabs to clean etc . I think the fault lies in lack of practice/expertise. And that's some beautiful microSD soldering , you show-off!
P.S- Will update this thread, in case someone lands up in same shit/ or curious to know if my 3ds will ever rise again from the dead. Thanks for the help!