As-Salamu 'Alaykum
sister Hareem, can you please answer following questions:
1) if milad is to gain reward; why didn't Allah's Rasoul (sal-allahu 'alayhi wa salam) told us to do? 2) why didn't the Salaf and the scholars of first 5-6 centuries do it? 3) are you telling us that Allah Ta'ala and His Prophet (sal-allahu 'alayhi wa salam) didn't tell us everything which could have benefited us in the hereafter?
btw the two adhan for the Juma'ah Salah was started by 'Uthman not 'Umar (may Allah be pleased with them) and the people of knowledge are well aware of the reasons and it doesn't justify the bid'ah.
I used to be like you almost 3 years ago and I never lost the argument because I was in constant denial.
So when you're ready for understanding the issue rather than with the intentions of refuting it then I'll explain it to you, inshaAllah.