How to scale one object/prefab exact same as other object/prefab size

Hello everyone,
I am trying to scale one object size same as other object size. I tried “Scale Constraint” component but it’s sometimes working while most time not (Maybe some bugs are still there in this component).
I am new in unity and game development.
Please tell me a solution. I can use unity or blender.
I am using unity 2019.2.11f1

Anyone help please