Did the Edict of Milan make Christianity the official religion of the Roman Empire?

No, the Edict of Milan did not make Christianity the official religion of the Roman Empire.12

Issued in 313 by emperors Constantine I and Licinius, the proclamation established religious toleration for all persons, allowing them to worship whichever deity they pleased. It granted Christians legal rights, such as the ability to organize churches and the return of confiscated property, effectively ending systematic imperial persecution. However, it did not prohibit traditional Roman religious practices, which remained legal and widely practiced.12

Christianity did not become the official state religion of the Roman Empire until 380, when Emperor Theodosius I issued the Edict of Thessalonica. While the Edict of Milan did not establish an official state faith, it was a pivotal turning point that permitted the Christian community to move beyond its status as a persecuted minority and set the stage for its future growth and influence in the Mediterranean region.12