@HappyDev I would always suggest going into a DCC tool (Blender, Maya, Max, Modo, etc.) to make corrections in your meshes in terms of position or scale. When you are working on a complex project with a lot of assets, making corrections to these types of problems in code will bloat your project and become untenable at some point. And when you come back to this six months later, you will have to unwind why you are doing all of this extra work until you remember that you had problems in the source file.
Granted, making changes in DCC tools isn’t always straight forward, especially when you have a rigged model that you did not make or have access to the author. You can spend a lot of cycles unwinding how a rig works and what can break when making changes. If you have budget, I would always suggest hiring an artist to fix the assets for you. If not, there are a lot of tutorials for Blender that can help you do some of this work, but it is a lot of new context to take on so I would suggest starting small and working up to being comfortable with more complex and rigged assets. Hope this helps in some way.