How do I import multiple text values from a CSV and also set the text format? (Drupal 9 migrate). SEE CODE COMMENTS

data.csv

migrate_plus.migration.example.yml

id: example
label: 'Example'
source:
  plugin: 'csv'
  delimiter: ','
  enclosure: '"'
  path: 'data.csv'
  header_offset: 0
  ids:
    - title

  fields:
    0:
      name: id
      label: id
    1:
      name: sentences
      label: sentences
    2:
      name: random_data
      label: random_data

process:
  type:
    plugin: default_value
    default_value: article

  title: title
  
  uid:
    plugin: default_value
    default_value: 1

  # This is how I would import a single value with the text format:
  field_random_data/value: random_value
  field_random_data/format:
    plugin: default_value
    default_value: 'basic_html'

  # How do I import multiple values separated by a delimiter '|' and also set the text format?
  # I am aware that sub_process does not work with scalar values, ref: https://www.drupal.org/project/drupal/issues/3175508
  # So the code below does not work. Any suggestions?
  # Could I use the new process plugin for 'MultipleValues', if yes, how?
  # https://git.drupalcode.org/project/migrate_plus/blob/HEAD/src/Plugin/migrate/process/MultipleValues.php
  field_sentences:
  -
    plugin: explode
    delimiter: '|'
    source: sentences
  -
    plugin: sub_process
    process:
      value: '0'
      format:
        plugin: default_value
        default_value: 'basic_html' # How can I set the text format after I have exploded the text string to an array?

destination:
  plugin: 'entity:node'
  default_bundle: article

The easiest way is to build a custom process plugin that returns the expected values. Something like this (untested).

function transform($value, MigrateExecutableInterface $migrate_executable, Row $row, $destination_property) {
    $exploded = explode('|', $value);
    return array_map(static function ($exploded_value) {
      return ['value' => $exploded_value, 'text_format' => 'basic_html'];
    }, $exploded);
}

migration.yml

field_sentences: 
  plugin: my_custom_process_plugin
  source: sentences

The easiest way is to build a custom process plugin that returns the expected values. Something like this (untested).

Okay, I understand. Sounds good. I was hoping there would be a contrib process plugin for this already ;)
Thank you for your help, @heddn !