Protobuf "Unresolved reference" with generated classes in Android Studio using Kotlin

it's my first time diving in with protobuf and jetpack's DataStore but I've encountered an issue which is quite confusing.

I've created my .proto file in src/main/java/proto, it's really simple:

syntax = "proto3";

option java_package = "com.test.appname.proto";
option java_multiple_files = true;

message WalkInfo {
  float distance = 1;
  bool run = 2;
}

Then I've written in kotlin a serializer class for some data in my app.

object WalkInfoSerializer : Serializer<Walker.WalkInfo>{
        override val defaultValue: Walker.WalkInfo
            get() = WalkInfo.getDefaultInstance()

        override fun readFrom(input: InputStream): Walker.WalkInfo {
            try {
                return WalkInfo.parseFrom(input)
            } catch (exception: InvalidProtocolBufferException) {
                throw CorruptionException("Cannot read proto.", exception)
            }

        }

        override fun writeTo(t: Walker.WalkInfo, output: OutputStream) {
            t.writeTo(output)
        }

    }

I've also set up my build.gradle file like this:

plugins {
    id 'com.android.application'
    id 'kotlin-android'
    id "com.google.protobuf" version "0.8.14"

}
...
dependencies {
    ...
    //DataStore
    implementation "androidx.datastore:datastore:1.0.0-alpha05"
    implementation 'com.google.protobuf:protobuf-javalite:3.14.0'
}

protobuf {
    protoc {
        artifact = "com.google.protobuf:protoc:3.10.0"
    }

    generateProtoTasks {
        all().each { task ->
            task.builtins {
                java {
                    option 'lite'
                }
            }
        }
    }
}

Everything works fine, the classes seem to be generated correctly and they even pop up in android studio's autocomplete. The problem is that I can't get the project to compile as I can't seem to find a way to resolve the "Unresolved Reference" for the methods generated (like getDefaultInstance(), parseFrom(), writeTo() Even by writing the full class path it won't work.

Am I missing something? I've tried to play around with build.gradle and the proto file with some settings I found in their documentation but I still couldn't get it to work

Thank you!