To user Tasklet or Chunk in this scenario

I have a job/task to read sub-folders/directory of a given folder/path. The path is dynamic, we get it from Controller. Currently, I have used Tasklet, there are 3 tasklets, one to read sub-directories, another to process it to prepare objects to save to DB and last one to write the processed data objects to a database.
The folders can have any number of sub-folders.Currently, I have used this code :

 Path start = Paths.get("x:\\data\\");
    Stream<Path> stream = Files.walk(start, 1);
List<String> collect = stream
		        .map(String::valueOf)
		        .sorted()
		        .collect(Collectors.toList());

To read all the sub folders at once.
I followed this https://www.baeldung.com/spring-batch-tasklet-chunk example of Tasklet implementation for the purpose. Is this the right approach ? I also need to run the Job asynchronously with multi-threading.
As there can be huge numbers of sub-folders, so there can be huge number of rowsorlist of data to process and write to the database.

Please suggest an appropriate approach.
I am learning Spring Batch, have done few examples on file read/process/write too and used Chunk approach for this.
But my job is to read sub-directories of a folder/path, so I cannot decide which approach to follow.

I have a similar scenario: I need to read all the files from a folder, process and write in db, (Doc)

@Configuration
@EnableBatchProcessing
public class BatchConfig {
@Bean
public Job job(JobBuilderFactory jobBuilderFactory,
Step masterStep) {
return jobBuilderFactory.get("MainJob")
.incrementer(new RunIdIncrementer())
.flow(masterStep)
.end()
.build();
}
@Bean
public Step mainStep(StepBuilderFactory stepBuilderFactory,
JdbcBatchItemWriter<Transaction> writer,
ItemReader<String> reader,
TransactionItemProcessor processor) {
return stepBuilderFactory.get("Main")
.<String, Transaction>chunk(2)
.reader(reader)
.processor(processor)
.writer(writer)
**.taskExecutor(jobTaskExecutor())**
.listener(new ItemReaderListener())
.build();
}
@Bean
public TaskExecutor jobTaskExecutor() {
ThreadPoolTaskExecutor taskExecutor = new ThreadPoolTaskExecutor();
taskExecutor.setCorePoolSize(2);
taskExecutor.setMaxPoolSize(10);
taskExecutor.afterPropertiesSet();
return taskExecutor;
}
@Bean
@StepScope
public ItemReader<String> reader(@Value("#{stepExecution}") StepExecution stepExecution) throws IOException {
Path start = Paths.get("D:\\test");
List<String> inputFile = Files.walk(start, 1)
.map(String::valueOf)
.sorted()
.collect(Collectors.toList());
return new IteratorItemReader<>(inputFile);
}
@Bean
@StepScope
public TransactionItemProcessor processor(@Value("#{stepExecution}") StepExecution stepExecution) {
return new TransactionItemProcessor();
}
@Bean
@StepScope
public JdbcBatchItemWriter<Transaction> writer(DataSource dataSource) {
return new JdbcBatchItemWriterBuilder<Transaction>()
.itemSqlParameterSourceProvider(new BeanPropertyItemSqlParameterSourceProvider<>())
.sql("INSERT INTO transaction (id, date, type) VALUES (:id, :date, :type)")
.dataSource(dataSource)
.build();
}

}