'PKIX path building failed - unable to find valid certification path to requested target' (behind corporate proxy with authenthication)

I'm trying my hand at flutter and react-native (I'm a beginner developer) and I have to build a small prototype for my company, but I can't get past the "run my first app" step due do a certificate error (detailed below).

I am behind a corporate ssl proxy that needs authentication, and we have an internal certificate chain as well. Now, I have zero experiences with certificates overall, so please be mindful of how a beginner would try to solve this.

I've combed the web for solutions and I'm at a loss about some of what I found:

  1. Some recommended using the InstallCert java app, but I can't due to proxy reasons and couldn't find a version that lets me set up my username and password for the proxy.

  2. Using the keytool to store the certificate into the java cacerts file, but I don't know which of the certificates I should install: The repository's (dl.google.com ?), or my company's.

  3. Would it be possible to download that .pom file and store it somewhere so it wouldn't need to access the internet to run? I can access that dl.google.com domain just fine and download it.

Below I've pasted my build.gradle file and the exact error.

buildscript {
    repositories {
        google()
        jcenter()
    }

    dependencies {
        classpath 'com.android.tools.build:gradle:3.2.1'
    }
}

allprojects {
    repositories {
        google()
        jcenter()
    }
}

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

task clean(type: Delete) {
    delete rootProject.buildDir
}

Error running Gradle: ProcessException: Process "C:\src\teste1\android\gradlew.bat" exited abnormally:

FAILURE: Build failed with an exception.

What went wrong: A problem occurred configuring root project 'android'. Could not resolve all artifacts for configuration ':classpath'. Could not resolve com.android.tools.build:gradle:3.2.1. Required by: project : Could not resolve com.android.tools.build:gradle:3.2.1. Could not get resource 'https://dl.google.com/dl/android/maven2/com/android/tools/build/gradle/3.2.1/gradle-3.2.1.pom'. Could not GET 'https://dl.google.com/dl/android/maven2/com/android/tools/build/gradle/3.2.1/gradle-3.2.1.pom'. sun.security.validator.ValidatorException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target Could not resolve com.android.tools.build:gradle:3.2.1. Could not get resource 'https://jcenter.bintray.com/com/android/tools/build/gradle/3.2.1/gradle-3.2.1.pom'. Could not GET 'https://jcenter.bintray.com/com/android/tools/build/gradle/3.2.1/gradle-3.2.1.pom'. sun.security.validator.ValidatorException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target