Image outside embed, only when image is a buffer.

import { AttachmentBuilder, EmbedBuilder } from 'discord.js';

const stats = async (client, interaction) => {
  const imageBuffer = await createChart(/*<chart data>*/);
  const attachment = new AttachmentBuilder(imageBuffer, 'chart.jpg');
  const embed = new EmbedBuilder()
    .setImage('attachment://chart.jpg');

  interaction.reply({ 
    embeds: [embed], 
    files: [attachment] 
  });
};

const attachment = new AttachmentBuilder(imageBuffer, 'chart.jpg');

const attachment = new AttachmentBuilder(path.join(process.cwd(), 'data/chart.jpg'), 'chart.jpg');