You cannot suffocate a Warden with blocks
Use stealth to avoid summoning it in the first place
Sneak near Shrieker blocks to prevent triggering them
Break or disable the Shrieker before it activates
Move away immediately if a Shrieker starts shrieking
Use ranged attacks from a safe distance
Trap the Warden in a hole or pit
Lead it away with noise and movement
Use strong weapons and armor if you must fight it
Run and hide until it despawns if possible