SkinnedMesh Combiner | Unity Asset by awtdev

Unity Tip: Bake objects into a single skinned mesh to allow for tons of animated guns (or other stuff I suppose) with a low performance cost!

I made a tool to combine skinned meshes together. Here you can see the performance impact using uncombined meshes can have, and with no visual difference between the two, it's literally free performance!

Make a Gameobject invisible in Unity - VionixStudio

How To Animate 3D Characters In Unity - Animator Component - GameDev Academy

Using Unity to Animate Game Characters | An Introduction to Unity Character Animation