Flutter – issue with kotlin, outdated and how to fix within gradle.build

I keep reading other accounts of this issue, how my version needs to be downgraded, but all the response say go to gradle.build, but mine does not match all the replies.

andriod/gradle.build

allprojects {
    repositories {
        google()
        mavenCentral()
    }
}

rootProject.buildDir = '../build'
subprojects {
    project.buildDir = "${rootProject.buildDir}/${project.name}"
}
subprojects {
    project.evaluationDependsOn(':app')
}

tasks.register("clean", Delete) {
    delete rootProject.buildDir
}

one said all i have to do is add(below) but where, i dont see my file match any of the ones ive seen answered here

ext.kotlin_version = ”

trying to resolve this issue to move forwards building, just recently appeared