running the same task on multiple agents in my Jenkins declarative pipeline

I have a block like:

stage('Clone on win10x64-b-ut') {
    agent {
        node {
            label 'win10x64-b-ut'
        }
    }
    steps {
        gitClone()
    }
}    

stage('Clone on win81x64-b-ut') {
    agent {
        node {
            label 'win81x64-b-ut'
        }
    }
    steps {
        gitClone()
    }
}

I want to run the same task in somewhat like a loop by just changing the labels. I want to eliminate redundancy as much as possible.

Take a look at this answer: https://stackoverflow.com/a/48421660/9498358

If you don't want to run stages in parallel (like in the linked answer), you can add a for loop inside the script block, so it will look something like this:

def generateStage(nodeLabel) {
    return {
        stage("Clone on ${nodeLabel}") {
            agent {
                node {
                    label nodeLabel
                }
            }
            steps {
                gitClone()
            }
        } 
    }
}

// ...

stage('Clone') {
    steps {
        script {
            def allNodes = ['win10x64-b-ut', 'win81x64-b-ut']

            for (def i = 0; i < allNodes.size(); i++) {
                generateStage(allNodes[i])
            }
        }
    }
}