What are the reasons for the downfall of the Western Roman Empire?

In the 4th century, the Roman Empire lost its power, moreover, in 395 a split occurred, which divided the lands of the empire into two parts – Western and Eastern. In addition, at that time, due to the migration of peoples, all the barbarian tribes in Europe began to move, the borders of the Western Roman Empire were simply bursting at the seams. The last straw was the invasion of the Huns in the 5th century, after which the lands of the empire were ravaged and the troops were defeated. After that, the final defeat of the empire was completed by the Germanic tribes.