How to render fields with ->view() in a render array table?

I am building a table in my build function of a block and want to render formatted field values or entities with the ->view(); method in a cell of my table.

As described here: https://www.computerminds.co.uk/articles/rendering-drupal-9-fields-right-way

I have a value like this:

$cell_value = $entity->field_name->view();

It outputs a render array. But when I put it in the table like this. Nothing shows up.

  $header = [
      'col1' => t('COL1'),
      'col2' => t('COL2'),
    ];
    $rows = [
      ['test col 1', $cell_value],
      ['test col 1', 'test'],
      ['test col 1', 'test'],
    ];
    return [
      '#type' => 'table',
      '#header' => $header,
      '#rows' => $rows,
    ];
  }

But when I render it like this:

return $cell_value;

I see a rendered value. Is there a way to render it in a table and how? Currently I am making every field manually which is very time consuming.