GC doesn't seem to run

package main

import (
	"fmt"
	"log"
	"math/rand"
	"strconv"
	"time"

	"github.com/dgraph-io/badger/v4"
)

var db *badger.DB

const charset = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"

func generateRandomString(length int) string {
	b := make([]byte, length)
	for i := range b {
		b[i] = charset[rand.Intn(len(charset))]
	}
	return string(b)
}

func main() {
	opts := badger.DefaultOptions("badger")
	opts.ValueLogFileSize = 1 << 20
	var err error
	db, err = badger.Open(opts)
	if err != nil {
		log.Fatal(err)
	}
	defer db.Close()

	fmt.Println("Start inserting 5 million items.")

	for i := 0; i < 5_000_000; i++ {
		err := db.Update(func(txn *badger.Txn) error {
			key := strconv.Itoa(i)
			value := []byte(generateRandomString(300))

			e := badger.NewEntry([]byte(key), value).WithTTL(30 * time.Second)

			err := txn.SetEntry(e)
			if err != nil {
				return err
			}
			return nil
		})

		if err != nil {
			log.Fatal("Error while inserting:", err)
		}
	}

	fmt.Println("Successfully inserted 5 million items.")

	startGarbageCollection()
}

func startGarbageCollection() {
	ticker := time.NewTicker(10 * time.Second)
	defer ticker.Stop()
	for range ticker.C {
	again:
		err := db.RunValueLogGC(0.01)
		fmt.Println(err)
		if err == nil {
			goto again
		}
	}
}