I have multiple objects with the same emission material. Is there a way to control the strength of the emission for each object?
The simplest for me would be to use the object pass-index.
This is supposed to be used in the compositor workspace but the value can be accessed in the shader editor. It is an integer value so if you want more precision, you can add a math node set to divide between the "Object Info" node and the "Emission" node.