Question What's the best way to hold guns?

I have a character animation controller that works well enough. It walks and runs and whatever, cool.
What is the best way to go about holding multiple types of guns?
I am thinking the rigging option with IK which I believe I can do. The thing is, I can set up the hands as IK at the right part of the gun, but how do I do all the animation in between, like equiping and 'stashing' the gun?
Is there a better way? Should I use Mixamo for everything?
A lot of resources tell you the basics and after that I find there to be limited resources, at least to my specific use case.
So how would you rig a full third person shooter character?

Layers, with mixamo.
Character controller with IK arms?

Just need to know I'm going in the right direction here.