If you try to create animations with shape keys for different actions in Blender, you'll have to connect these animations to driver bones to make this work. To make the setup easier you can use this Addon to create ready to use driver bones which are connected to shape keys.

Usage:

• Select all objects for which you want to create driver bones
• Shift + A -> Armature -> Driver Bones

Installation:

• Download DriverBonesGenerator.py
• Open Blender and go to Edit -> Preferences -> Addons
• Choose Install from Disk and select the downloaded file

Get it from here: https://s3rdia.itch.io/driver-bone-generator