with what you shared we cant tell what that variables output looks like (${intensity.percent})
if you can post the exact text that is passed in payload 1 then we could help find the right solution or the right regex pattern to get just the percent number.
or if payload 1 is already just a number and your are trying to use payload 1 in some way then we will need more details on what your goal is, you can use payloads by using {1} = Payload 1, {2} = Payload 2, {3} = Payload 3....