Go to BP_SmartAIComponent and create a new variable called Climb Speed set the default value to 1.2, tooltip below and set the category to Climbing Settings then tick Instance Editable.
Tool tip Below
“This is the speed multiplier for AI climbing this allows you to control the speed the AI climbs and vaults”
Next add the node shown in the image below.
Next go to the BP_MasterAICharacter and then to the Valt Climb Events collapsed node and change the value shown in the image below.